catalysis research center graduate academy 2016 · sentations (.pdf or .ppt format) prior to the...

Catalysis Research CenterGraduate Academy 2016

focus topic: photocatalysis

June 5-8th 2016

TUM Science and Study Center Raitenhaslach

crc.tum.de/graduateacademy

Book of Abstracts

Catalysis Research CenterTechnical University of Munich

CRC Graduate Academy 2016 supported by

Imprint

The CRC Graduate Academy 2016 is organized in the framework of the DFH/UFA sponsored PhD-Track PhD7-12. dfh-ufa.org

Program CommitteeProf. Ueli Heiz, Prof. Conrad Becker, Prof. Corinna Hess, Dr. Florian Schweinberger

Local Organization CommitteeProf. Corinna Hess, Dr. Florian Schweinberger,Dr. Dimitrios Mihalios, Maximilian Krause, Joachim Leibold, Irmgard Grötsch

PublisherProf. Ueli Heiz, Academic Director, TUM CRC

Layout and EditorDr. Florian Schweinberger, May 2016

graduate school ofnanoscience

munich marseille

Faculty Graduate Centers CH and PH

Catalysis Research CenterGraduate Academy 2016

focus topic: photocatalysis

June 5-8th 2016

TUM Science and Study Center Raitenhaslach

crc.tum.de/graduateacademy

Book of Abstracts

Catalysis Research CenterTechnical University of Munich

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Information

Venues

TUM Science & Study Center RaitenhaslachRaitenhaslach 3-9, 84489 Burghausen, Germanyraitenhaslach.tum.de

Hotel GlöcklhoferLudwigsberg 4, 84489 Burghausen, Germanyhotel-gloecklhofer.de

Hotel BurgblickAch 31, 5122 Ach, Austriaaltstadthotels.net

Information for speakersTalk durations: 20 min = 15 min Presentation + 5 min Discussions,30 min = 20 min Presentation + 10 min Discussion.

We kindly ask all speakers to provide the pre-sentations (.pdf or .ppt format) prior to the start of the session.

Information for poster presentationsFree choice of poster wall; please hang up your poster during the first coffee break and keep them available through the event.

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Content

Schedule 6

Lectures 9Prof. Hermenegildo Garcia 10Dr. Francesco Allegretti 11Constantin Walenta 12Maïmouna Diouf 13Prof. Richard Fischer 14Dr. Oliver Thomys 15Felix Kirchberger 16Sebastian Standl 17Marian Rötzer 18Prof. Ib Chorkendorff 19Prof. Conrad Becker 20Jacob Ducke 21Dr. Daniel Ferry 22Dr. Sanyal Udishnu 23Prof. Hans Niemantsverdriet 24Dr. Thomas Cornelius 25Jürgen Kraus 26Martin Schwarz 27Dr. Martin Strassburg 28Kai Sanwald 29Dr. Anthoula Papageorgiou 30Manuel Kaspar 31Ruth Haas 32Prof. Miquel Costas 33

Posters 35Johannes Bartl 36Christoph Brenninger 37Carla Courtois 38Konstantin Epp 39Stefan Ewald 40Steffen Garbe 41Prof. Suzanne Giorgio 42Dr. Oliver Gutiérrez 43Han Li 44Alena Hölzl 45Benjamin Hofmann 46Julius Hornung 47Takaaki Ikuno 48Dennis Knogler 49Sebastian Kollmannsberger 50Maximilian Krause 51Paul Leidinger 52Dr. Tony Lelaidier 53Li Jiang 54Pankaj Madkikar 55Iman Marhaba 56Amina Merabet 57Vincent Mesquita 58Elmar Mitterreiter 59Daniel Rutz 60Christian Schüler 61Jan Schwämmlein 62Paul Stockmann 63Moritz Wolf 64Ioannis Zachos 65

Participants 66

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Sunday – June 5th

15:00 Bus shuttle from Munich to Burghausen

16:00 Pick-Up: Airport MUC

16:00 Hotel Check-In Registration

19:00 Welcome Dinner Hotel Glöcklhofer

Monday – June 6th

08:00 Breakfast at Hotel

09:00 Bus shuttle to Raitenhaslach

09:30 Welcome note

10:00 Keynote – Hermenegildo Garcia

11:00 Coffee break

11:30 Tour of the Raithenhaslach Monastery

12:30 Lunch break

14:00 Talk – Francesco Allegretti 14:30 Talk – Constantin Walenta14:50 Talk – Maïmouna Diouf

15:10 Coffee break

MuniCat session16:00 Introduction – Richard Fischer16:20 Talk – Oliver Thomys16:50 Talk – Felix Kirchberger17:10 Talk – Sebastian Standl17:30 Talk – Marian Rötzer

18:15 BBQ

20:00 Poster Session & Informal Discussions

22:30 Bus shuttle to Hotel

Schedule

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Tuesday – June 7th

08:00 Breakfast at Hotel


09:30 Keynote lecture – Ib Chorkendorff

10:30 Coffee break

11:00 Talk – Conrad Becker11:30 Talk – Jacob Ducke11:50 Talk – Daniel Ferry12:10 Talk – Sanyal Udishnu

12:30 Lunch break

14:00 Workshop – Hans Niemandsverdriet

16:00 Coffee break

16:30 Talk – Thomas Cornelius17:00 Talk – Jürgen Kraus17:20 Talk – Martin Schwarz

17:45 ‚Looking Beyond Your Own Backyard‘-Keynote – Martin Strassburg

19:00 Conference Dinner Conferment of MuniCat Poster Awards

21:30 Bus shuttle to Hotel

Wednesday – June 8th

08:00 Breakfast at Hotel Check-out


09:30 Talk – Kai Sanwald09:50 Talk – Anthoula Papageorgiou10:20 Talk – Manuel Kaspar10:40 Talk – Ruth Haas

11:00 Coffee break

11:30 Keynote lecture – Miquel Costas

12:30 Closing remarks 13:00 Lunch

14:00 Bus shuttle from Raitenhaslach to Munich

16:00 Drop-Off: Airport MUC

Schedule

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Lectures

10

Technical University of Valencia, Av. de los Naranjos s/n, Spain

[email protected]

Prof. Hermenegildo Garcia

Photocatalysis for the production of solar fuels

After a short introduction in the concept of solar fuels and the use of solar photocatalysis for their production, the presentation will focus on the materials developed as photocatalysts by our group including plasmonic photocatalysts, metal organic frameworks and modified graphenes.

[1] Gomes Silva, C., Juarez, R., Marino, T., Molinari, R., Garcia, H., J. Am. Chem. Soc, 133 (3), 595-602 (2011). [2] Latorre-Sanchez, M., Primo, A., Garcia, H., Angew. Chem. Int. Ed. 52 (45), 11813-11816 (2013) [3] Neatu, S., Antonio Macia-Agullo, J., Concepcion, P., Garcia, H., J. Am. Chem. Soc 136 (45), 15969 (2014). [4] Sastre, F., Puga, A.V., Liu, L., Corma, A., & Garcia, H., J. Am. Chem. Soc 136 (19), 6798 (2014). [5] Silva, C.G., Luz, I., Llabres i Xamena, F.X., Corma, A., Garcia, H., Chemistry-a European Journal 16 (36), 11133 (2010).

Keynote

11

Allegretti Francesco1, Deimel Peter S.1, Duncan David A.1,2, Casado-Aguilar Pablo1, Paszkiewicz Mateusz1, Acres Robert G.3, Wiengarten Alissa1, Papageorgiou Anthoula C.1, Klappenberger Florian1, Auwärter Willi 1, Feulner Peter 1, Barth Johannes V. 1

1 Technical University of Munich, Catalysis Research Center and Physics Department, Chair of Mo-lecular Nanoscience and Chemical Physics of Interfaces, James-Franck-Str. 1 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

2 Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0QX, UK

3 Sincrotrone Trieste, Strada Statale 14, km 163.5, 34149 Basovizza, Trieste, Italy

[email protected]

Dr. Francesco Allegretti

Atomic-scale investigation of an in-situ prepared single layer of oxo-titanium porphyrins on Ag(111) for model pho-tocatalytic studies

TiO2 is a promising candidate to convert sunlight into chemical energy via photocatalytic splitting of water, however, a major draw-back is that the efficiency is generally limited by the high band gap of TiO2 and an energetically favourable backward reaction [1]. In 2012, theoretical work by A. L. Sobolewski and W. Domcke predic-ted that the metal-organic complex oxo-titanium porphyrin (TiOP) can both photocatalytically split water and quench the backwards reaction [2]. Motivated by investigations of O. Morawski et al. that experimentally confirmed the proposed process by detection of OH• radicals generated upon irradiation to light of 445 and 570 nm wavelength [3], we aim to study the photocatalytic properties of TiOP single layers under model conditions in ultra high vacuum (UHV).

In this vein, we report here on the creation and characterizati-on in UHV of a layer of oxo-titanium tetraphenyl porphyrin (TiO-TPP), adsorbed on a well-defined single-crystal surface (Ag(111)), upon metallation with Ti and subsequent exposure to molecular oxygen of a free-base porphyrin species (2H-TPP) [4]. Through state-of-the-art surface science methodology involving photoelec-tron spectroscopy, X-ray absorption spectroscopy, photoelectron diffraction, scanning tunnelling microscopy and temperature pro-grammed desorption techniques, we gain atomistic insight into the structural and chemical changes leading to the formation of an oxo-Ti group oriented perpendicular to the metal surface and pointing outwards. The comparison with a related corrole molecule is also presented.

The prepared single layer of TiO-TPP represents an intriguing model system for future atomic-level investigations of the photo-chemistry of adsorbed metal-organic complexes.

[1] M. Ni et al., Renew. Sustainable Energy Rev. 11, 401 (2007).[2] A. L. Sobolewski, W. Domcke, PCCP 14, 12807 (2012).[3] O. Morawski et al., PCCP 16, 15256 (2014).[4] D. A. Duncan et al., Chem. Commun. 51, 9483 (2015).

Talk

12

Constantin Walenta1 ,2, Sebastian Kollmannsberger1, Martin Tschurl1, Ueli Heiz1,2

1 Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Physical Chemistry, Lichtenbergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

2 Nanosystems Initiative Munich (NIM), Schellingstr. 5, 80799 Munich, Germany

[email protected]

Constantin Walenta

Ethanol photocatalysis on TiO2(110): a mechanistic study

Metal cluster-semiconductor systems are promising new hybrid materials for combined light harvesting and conversion of photon energy into chemical energy. As promising materials Au/TiO2 sys-tems attracted considerable attention over the last years [1,2]. The most explored model reaction is photochemical water splitting, but the H2-production is still limited. Another renewable feedstock of interest is ethanol, because alcohols are the main product from biofermentation and as such are ideal precursors for biomass in general [3].

In order to design ideal metal cluster-semiconductor hybrid sys-tems and to maximize the hydrogen production yield, the under-standing of the semiconductor’s surface photochemistry is of paramount importance. To ensure very well defined conditions, rutile TiO2(110) is studied under UHV conditions. Exemplified on titania, we demonstrate how the mechanisms of photochemical reactions can be elucidated via the judicious choice of different experiments. It is shown, that ethanol is photooxidized to acet-aldehyde. Although formally two hydrogen atoms remain from the stoichiometric reaction equation, no molecular hydrogen produc-tion is observed [4]. The hydrogen forms water on the surface which poisons the photocatalyst by site-blocking on a defect-rich surface. This mechanism enables even the interpretation of ambi-ent photocatalytic systems.

[1] Murdoch et al., Nat Chem, 2011, 3, 6. [2] Yoshida et al., J. Am. Chem. Soc., 2009, 131, 37. [3] Navarro et al., Energy Environ. Sci., 2009, 2, 1. [4] Walenta et al., Phys. Chem. Chem. Phys., 2015, 17, 35.

Talk

13

Allegretti Francesco1, Maïmouna Diouf1, Lionel Santinacci1, Maïssa Barr1, Bruno Fabre2, Loïc Joanny2, Francis Gouttefangeas2, Gabriel Loget2

1 CINaM UMR 7325, Aix Marseille Université, CNRS, 13288, Marseille, France.

2 Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France.

[email protected]

Talk

Maïmouna Diouf

Atomic layer deposition of TiO2 onto anodic black Si for water photosplitting

Producing solar fuel by water photoelectrolysis is a promising solution for energy generation and storage. That has attracted lot of interest towards development of photoelectrochemical cells (PECs) that produce H2 and O2 from water splitting using solar light [1]. PECs are generally based on semiconductor surfaces, immersed in an aqueous electrolyte, that can use light energy to drive electrochemical reactions such as water oxidation and reduction. Silicon is largely used as a photoelectrode in these PECs because of its high abundance and convenient bandgap energy [2]. However, it is reflective and corrodes under operating conditions in aqueous media. Micro-structuration can be used to decrease reflectivity while increasing surface area without losing any bulk properties of Si [3]. It has been reported that TiO2 thin film provide protection against corrosion for silicon photoelectrodes when they are appropriately coated [4].

Therefore, photon absorption is increased leading to better PECs efficiency. In this presentation , we report a rapid and cheap meth-od to structure n-type Si with micro-pores. Antireflective silicon, also named black silicon is has been produced by photoelectro-chemical etching and subsequent alkaline etching of flat silicon. Atomic layer deposition (ALD) is a unique method to conformably coat high aspect-ratio substrates. ALD have been used to coat the black silicon with anatase TiO2. These protected black silicon photoanodes exhibit greater photocurrents under simulated sun-light than their planar counterparts.

[1] K. Sivula and R. van de Krol, Nat. Rev. Mater., 1, 2, 15010, (2016). [2] K. Sun, S. Shen, Y. Liang, P. E. Burrows, S. S. Mao, and D. Wang, Chem. Rev., 114, 17, 8662, (2014). [3] X. Liu, P. R. Coxon, M. Peters, B. Hoex, J. M. Cole, and D. J. Fray, Energy Environ. Sci., 7, 10, 3223, (2014). [4] S. Hu, M. R. Shaner, J. A. Beardslee, M. Lichterman, B. S. Brunschwig, and N. S. Lewis, Science, 344, 6187, 1005, (2014).

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Coordinator MuniCat, Technical University of Munich; Chemistry Department, Chair of Chemical Technology 1, Lichten-bergstraße 4, 85748 Garching, Germany

[email protected]

Prof. Richard Fischer

Munich Catalysis – The strategic alliance of TUM and Clariant

MuniCat comprises the strategic research alliance between TUM and the specialty chemicals company Clariant in the area of catalyst development. Clariant’s Catalysts business unit is a leading global developer and producer of catalysts for industrial processes.

MuniCat follows an “industry on campus” approach: TUM scien-tists and Clariant researchers work together to resolve questions of fundamental and applied research in chemical catalysis. Since its inception in 2010, more than 50 PhD, master and bachelor stu-dents have worked on ten successful MuniCat research projects Located in the newly build and recently opened TUM Catalysis Research Center, MuniCat will continue the established research projects and continue with vanguard, novel project ideas in the future.

The presentation will give an overview of MuniCat’s organization, its vision and mission. Selected examples will explain how Muni-Cat is working, to give the audience a basis for the following pres-entations of the “Clariant Slot” of the CRC Graduate Academy.

munich-catalysis.tum.de

Talk

15

K. Köhler1, K.-O. Hinrichsen2, O Thomys1, F. Koschany2, D. Schlereth2

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Associate Professorship of Inorganic Chemistry, Lichtenbergstraße 4 and Ernst- Otto-Fischer-Str. 1, 85748 Garching, Germany

2Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Chemical Technology 1, Lichten-bergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Dr. Oliver Thomys

New catalysts for the hydrogenation of carbon dioxide to methane for energy-storage

The methanation of carbon dioxide is referred to as a suitable concept for energy storage connected to renewable energies [1]. The aim of the COOMeth project was the development of efficient catalysts for this so called Sabatier-process. Therefore, several hundred catalysts were prepared by various impregnation techniques and co-precipitation, employing DoE and Data Min-ing strategies. For the catalytic tests, a parallel testing unit was applied. Promising catalysts were further characterized in their physical and structural properties. Kinetic measurements were conducted to explore the characteristics of the highly exothermic reaction as well as the long-term activity of the catalysts. Further-more, a kinetic model was developed, enabling the prediction of the intrinsic kinetic of state-of-the-art catalysts under real process conditions [2].

Highly active catalysts with increased stability towards the de-manding process conditions have been developed in this project supported by BMBF within a cooperation of two TUM-groups (K.-O. Hinrichsen, K. Köhler) and five industry partners (Clariant AG/MuniCat, Wacker Chemie AG, MAN SE, Linde AG, E.ON SE). In addition, screening experiments revealed promising opportun-ities to further decrease the metal loading. These positive results were confirmed by test runs under real process conditions, using a pilot reactor provided by MAN.

[1] M. Specht, M. Sterner, B. Stürmer, V. Frick, B. Hahn, Renewable Power Methane - Stromspeicherung durch Kopplung von Strom- und Gasnetz - Wind/PV-to-SNG, Registered by ZSW, on 09.04.2009. Patent No: 10 2009 018 126.1. [2] F. Koschany, D. Schlereth, O. Hinrichsen, Applied Catalysis B: Environmental, Juli 2015.

Talk

16

F. Kirchberger1, S. Müller1, Y. Liu1, M. Sanchez-Sanchez1, J. A. Lercher1

1 Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Chemical Technology 2, Lichten-bergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Felix Kirchberger

Methanol to olefins: tackling the problem of catalyst deactivation

Catalytic conversion of methanol to hydrocarbons on solid acids, especially on H-ZSM-5 and SAPO-34, has attracted great atten-tion and effort in the past decades in respect of methane and syn-gas transformation as well as gasoline (MTG) and olefin (MTO) production. One of the main problems arising in these processes is the fast deactivation of the zeolite catalyst due to accumula-tion of coke. Understanding the processes which lead to carbon deposition and the associated catalyst deactivation is challenging, because along conventional plug-flow reactors (PFR) the com-plex reaction network and the decreasing methanol concentration generates different reaction zones where carbonaceous deposits vary drastically. While the different reaction zones for MTO have been discussed, the concentration and nature of carbon deposits associated to each zone and the specific impact of such coke in the overall deactivation is not well known yet.

In this work, the kinetics of carbon formation under MTO was studied in a back-mixed reactor (CSTR) in order to generate homogenously coked samples with different extent of deactiva-tion. In addition, the different zones of a PFR were simulated by connecting several reactors in line. The study was conducted at short times on stream and partial conversions, with the aim of monitoring the first chemical reactions conducting to formation of carbonaceous deposits in each zone.

[1] S. Müller, Y. Liu, M. Vishnuvarthan, X. Sun, A. C. van Veen, G. L. Haller, M. Sanchez-Sanchez, J. A. Lercher, Journal of Catalysis, Volume, 325, 48-59, 2015.

Talk

17

Sebastian Standl1, Tassilo von Aretin1, Markus Tonigold2, Kai-Olaf Hinrichsen1


2Clariant Produkte (Deutschland) GmbH, D-83052 Bruckmühl, Germany

[email protected]

Sebastian Standl

Boosting the yield: how single-event kinetics can help out of the selectivity trap

Lower olefins are widely used in the polymer industry. The ever increasing demand for propene favors catalytic cracking since it offers possibilities of influencing the product spectrum [1]. To obtain a fundamental kinetic model which is independent of reac-tion conditions or feed, the single-event concept can be used to describe the complex reactivity of olefins on the catalytic surface [2]. This procedure allows extrapolation out of the experimental-ly covered range so that both process optimization and reactor design are possible [3]. In this work, kinetic parameters for crack-ing of 1-pentene on ZSM-5 are used to maximize propene yields combined with low ethene production and high conversion. This is done by implementing two different reactor solutions using fun-damental kinetic parameters which have been determined in an earlier work with kinetic data from 165 experiments [2].

The first reactor concept is a two-zone reactor [4]. The influence of temperature is used here to decouple propene and ethene yields. An initial low temperature zone which favors dimerization is followed by a high temperature zone which shows pronounced cracking of higher olefins. This setup shows high flexibility in ad-justing the product spectrum. The second solution is a recycle reactor where all olefins higher than propene are separated from the product stream and led back to the reactor inlet. The kinetic model shows that the optimum operating point is a compromise between desired product yields and process efficiency: low tem-peratures lead to high propene to ethene ratios, but also cause high recycle ratios.

[1] Mokrani, T., Scurrel, M., Cat. Rev. Sci. Eng. 51 (2009) 1. [2] von Aretin, T., Schallmoser, S., Standl, S., Tonigold, M., Lercher, J.A., Hinrichsen, O., Ind. Eng. Chem. Res. 54 (2015) 11792.[3] Thybaut, J.W. and Marin, G.B., J. Catal. 308 (2013) 352.[4] von Aretin, T., Standl, S., Tonigold, M., Hinrichsen, O., Chem. Eng. J., in press, doi: 10.1016/j.cej.2016.04.089

Talk

18

Marian D. Rötzer1, Maximilian Krause1, Andrew S. Crampton1, Florian F. Schweinberger1, Heiz U.1


[email protected]

Talk

Marian Rötzer

Acetylene hydrogenation on Pd nanoparticles – new insights into a classical system

The selective hydrogenation of acetylene in the presence of ethene is of major industrial importance in order to produce high quality ethene as a feedstock for polymerization, oxidation and halo-genation. Because of its intrinsic high selectivity to form ethyl-ene, palladium is the metal of choice for this reaction with the Lindlar-type catalyst being a famous example. Although this type of catalyst has been successfully operated for almost 50 years, recent developments on both, theoretical and experimental level have shown that the surface chemistry on these palladium metal particles is enriched by the interplay of several parameters, e.g. subsurface hydrogen and carbon deposits, which all influence the catalytic performance.

To this end, we investigated the selective hydrogenation of acetyl-ene on supported palladium nanoparticles in the sub-nm regime consisting of 20-35 atoms under ultra-high vacuum conditions (UHV). The reactivity of these nanoparticles is tested by using a pulsed molecular beam technique and it is shown that already these small particles exhibit properties of larger nanoparticles like the formation of subsurface hydrogen species. The properties of these species can be effectively tuned by the appropriate choice of support and effect the intrinsic selectivity of the supported metal particles. Furthermore the surface of these particles is charac-terized by IRRAS in order to determine the formation of carbon-aceous species under the applied reaction conditions. The results of the selective hydrogenation of acetylene are compared to those of the hydrogenation of ethylene, and important differences are highlighted.

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Keynote

Prof. Ib Chorkendorff

Photo-electro-chemical water splitting and the making of renewable chemicals.

Hydrogen is the simplest solar fuel to produce and in this pre-sentation we shall give a short overview of the pros and cons of various tandem devices [1,2]. The large band gap semiconductor needs to be in front, but apart from that we can chose to have either the anode in front or back using either acid or alkaline condi-tions. Since most relevant semiconductors are very prone to corro-sion the advantage of using buried junctions and using protection layers offering shall be discussed [3-5].In particular we shall show how doped TiO2 is a very generic protection layer for both the anode and the cathode [6]. Next we shall discuss the availability of various catalysts for being coupled to these protections layers and how their stability and amount needed may be evaluated [7-9]. Examples of half-cell reaction using protection layers for both cathode and anode will be discussed though some of recent ex-amples both under both alkaline and acidic conditions. Notably NiOx promoted by iron is a material that is transparent, providing protection, and is a good catalyst for O2 evolution [10]. Si is a good low band gap semiconductor and the optimal thickness of this in a tandem device will be discussed [11]. Finally if time allows we shall also discuss the possibility of making high energy density fuels by hydrogenation of CO2 instead of hydrogen evolution [12]. We shall here show how we can investigate the recent ethanol synthesis on oxygen derived Cu found by Kanan et al. and show how acetaldehyde seems to be an important intermediate [13].

[1] A. B. Laursen et al, Energy Environ. Sci. 5 5577 (2012).[2] B. Seger et al., Energy Environ. Sci. 7 2397 (2014).[3] B. Seger, et al., Angew. Chem. Int. Ed., 51 9128 (2012).[4] B. Seger, et al., J. Am. Chem. Soc 135 1057 (2013).[5] B. Seger, et al., J. Mater. Chem. A, 1 (47) 15089 (2013).[6] B. Mai et al., J. Phys. Chem. C 119 15019 (2015).[7] R. Frydendal et al., Chem.Elec.Chem 1 2075 (2014).[8] E. A. Paoli, et al., Chemical Science, 6, 190 (2015).[9] E. Kemppainen et al., Energy Environ. Sci., 8 2991 (2015).[10] B. Mei et al., J. Phys. Chem. Lett. 5 1948 (2014).[11] B. Dowon et al., Energy Environ. Sci.. 8 650 (2015).[12] A. Verdaguer-Casadevall et al., J. Am. Chem. Soc. 137 9808 (2015).[13] E. Bertheussen et al., Angew. Chem., 55 1450, (2016).

CINF, Department of Physics, Department of Physics, The Technical University of Denmark., Denmark

[email protected]

20

Conrad Becker1, Thomas Léoni1, Tony Lelaidier1, Anthony Thomas1, Olivier Siri1

1 Aix-Marseille Université, CNRS, CINaM - UMR 7325, Marseille, France

[email protected]

Prof. Conrad Becker

Single molecule chemistry by STM

Scanning tunnelling microscopy is today one of the standard tech-niques for the analysis of solid surfaces. It allows to elucidate the geometric and electronic structure of surfaces with atomic resolution. Recent research has shown that electron tunnelling can also be used to chemically modify surfaces and adsorbates either by manipulation or by inelastic electron transfer processes. In this presentation we will review the possibilities of chemically modifying adsorbed molecules using the STM under UHV con-ditions. The focus will be on dehydrogenation processes, which have been observed for isolated molecules but also in compact molecular layers.

We will use recent results obtained for dihydrotetraazapentacene (DHTAP) on Au(111) to illustrate the power of the method for syn-thesizing molecules, which cannot be produced by conventional organic synthesis. In one particular case the STM can be used to produce tetraazapentacene (TAP) by dehydrogenation of the NH-groups of DHTAP and this with molecular resolution in compact layers. TAP can be thus produced in the first and the second monolayer. The decoupling of the DHTAP molecules in the second molecular layer further allows for the creation of radicals by either single hydrogenation or dehydrogenation.

We will discuss the potential applications of this method for the production of entire molecular layers of TAP. This could lead to semiconducting molecular layers, which should possess similar properties as pentacence layers.

Talk

21

Jacob Ducke1, Yuanqin He1, Alissa Wiengarten1, Felix Bischoff1, Manuela Garnica1, Willi Auwärter1

1 Technical University of Munich, Catalysis Research Center and Physics Department, Assistant Professorship of Molecular Engi- neering at Functional Interfaces, James-Franck-Str. 1 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Jacob Ducke

Surface-assisted reactions of porphyrins investigated by nc-AFM

Surface-assisted covalent linking of precursor molecules enables the fabrication of low-dimensional nanostructures. Here, we present a temperature-induced covalent dehydrogenative coup-ling mechanism of free-base porphine (2H-P) units. The oligomers resulting from a homocoupling reaction have been characterized by a multitechnique approach and theoretical modelling, how-ever an atomically resolved study of the resulting nanostructures was lacking [1]. With nc-AFM we are able to identify the resulting bonding motifs and can confirm the proposed structural models.

Furthermore, we used a similar coupling mechanism to func-tionalize the edges of epitaxial grown graphene on Ag(111) with 2H-P [2]. Distinct configurations are identified and resolved at the graphene edges with submolecular precision. Functionalization reactions like metallation of the 2H-P and subsequent axial ligation of adducts are conserved for porphines coupled to graphene. Thus, our findings bear promise for functionalized graphene nano-structures and for the formation of tailored oligomeres on surfaces.

[1] Wiengarten, A., et al., J. Am. Chem. Soc. 136 (2014): 9346.[2] He, Y., et al. ”Fusing tetrapyrroles to graphene edges by surface-assisted covalent coupling.” submitted.

Talk

22

Daniel Ferry1, Iman Marhaba1, Philippe Parent1, Tom Z. Regier2

1Aix-Marseille Université, CINaM, campus de Luminy case 913, F-13009 Marseille - France

2Canadian Light Source, Saskatoon, SK, S7N 2V3, Canada

[email protected]

Dr. Daniel Ferry

Structure, chemistry and optical properties of aircraft soot nanoparticles

Aerosols affect the climate system through various physical pro-cesses as they can scatter and absorb solar radiation, emit ther-mal radiation, or act as cloud condensation nuclei that modify the cloudiness coverage, changing its albedo. Carbonaceous solid aerosols resulting from anthropogenic processes or biomass burn-ing are one of the most significant contributors to global climate change with respect to their impact on radiative forcing [1]. But, it is not clear to date how their structural and chemical characteris-tics affect their reactivity with atmospheric gases and their optical properties in the UV-visible spectrum.

In this context, a multi-scale examination of the morphology and structure of aircraft soot particles is performed by High-Resolution Transmission Electron Microscopy. The chemical speciation of carbon and oxygen is determined from X-ray Photoelectron Spec-troscopy and Near-Edge X-ray Absorption Fine Structure measure-ments, providing important informations on the nature of structural and chemical defects [2]. Ultraviolet Photoemission Spectroscopy and specific extinction measurements in the UV-visible spectrum [3] enable determining interband electronic transitions and their relation to structural defects and chemistry of nanoparticles. On the basis of these interband electronic transitions, optical prop-erties of soot nanoparticles can therefore be understood in term of structural and chemical characteristics at the molecular level. The next step consists in studying interactions between soot par-ticles and atmospheric radicals/molecules (especially water) as well as UV-visible radiations interaction with soot. This part of the work aims at understanding the nucleation and ice growth processes during contrails/clouds’ formation, and soot ageing processes in the atmosphere.

[1] Lohmann, U. and Feichter, J. (2005) Atmos. Chem. Phys. 5, 715. [2] Parent, Ph., Laffon, C., Marhaba, I., Ferry, D., Regier, T.Z., Ortega, I.K., Chazallon, B., Carpentier, Y., Focsa, C. (2016) Carbon 101, 86-100. [3] Bescond, A., Yon, J., Ouf, F.-X., Rozé, C., Coppalle, A., Parent, P., Ferry, D., Laffon, C. (2016) subm. to Journal of Aerosol Science.

Talk

23

Sanyal Udishnu1, Song Yang1, Oliver Y. Gutiérrez1, Johannes A. Lercher1


[email protected]

Talk

Dr. Sanyal Udishnu

Manipulation of reaction pathways in the electrocatalytic hydrogenation of phenol

The realization of zero-carbon-footprint energy carriers will depend on the availability of H2 synthesized without CO2 emission and its suitable storage in chemical bonds. The electric energy thus ob-tained from renewable sources such as wind, solar, and hydropow-er may be potentially stored as hydrocarbon energy carriers, e.g., as transportation fuels [1]. Electrocatalytic hydrogenation (ECH) is one of the conceptually most promising routes to a decentralized production of energy carriers. Overall, the aim of the ECH is to use protons reduced at the cathode to hydrogenate organic reactants, while oxidization equivalents produced at the anode could be used to mineralize by-products [2-3].

Various carbon-supported metal catalysts such as Pt/C, Pd/C and Rh/C are found to be effective towards the ECH of phenol at ambient condition, wherein Rh/C is the most active [4]. The ECH rates were manipulated by tuning the negative potential which resulted in varying concentration of adsorbed hydrogen on the metal surface. By increasing the negative potential from –0.4 to –0.9 V (vs Ag/AgCl) ECH rates were enhanced by 40 times. ECH is always associated with the hydrogen evolution reaction (HER), a side process that reduces the faradic efficiency. We showed that controlling the particle size has tremendous influence on the faradic efficiency of the ECH process. By varying the size of metal particles, it is found that small particles favour the HER whereas large particles favour hydrogenation of aromatic hydrocarbons. Thus, ECH rates and selectivity can be controlled by judicious selection of potential and size of the metal particles at the cathode.

[1] Xin, L.; Zhang, Z.; Qi, J.; Chadderdon, D. J.; Qiu, Y.; Warsko, K. M.; Li, W. ChemSusChem 2013, 6, 674.[2] Li, Z.; Garedew, M.; Lam, C. H.; Jackson, J. E.; Miller, D. J.; Saffron, C. M. Green Chem. 2012, 14, 2540.[3] Li, Z.; Kelkar, S.; Raycraft, L.; Garedew, M.; Jackson, J. E.; Miller, D. J.; Saffron, C. M. Green Chem.[4] Song, Y.; Gutiérrez, O. Y.; Herranz, J.; Lercher, J. A. Appl. Catal., B 2016, 182, 236.

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Syngaschem BV, DIFFER, De Zaale 20, 5612 AJ Eindhoven PO Box 6336, 5600 HH Eindhoven, The Netherlands

[email protected]

Workshop

Prof. Hans Niemantsverdriet

Presenting science

Presenting your scientific work in talks, posters and articles largely follows the same principle: Focus on a Crystal Clear Message intended for a Specific Audience. This workshop emphasizes how to present science in publications, based on a course developed for prospective authors in the Journal of Catalysis.

A free video version of a similar course on article writing by Prof. Roel Prins can be watched on www.catalysiscourse.com, while a summary handout for the entire course Presenting Science is available on www.scientificleaders.com.

catalysiscourse.comscientificleaders.com

25

Cornelius Thomas1, Ren Zhe1, Robach Odile2, Micha Jean-Sébasti-en2, Mocuta Cristian3, Borges Araujo Eudes3, Thomas Olivier1

1 Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 13397 Marseille, France

2 CRG-IF BM32 Beamline at the Euro-pean Synchrotron (ESRF), CS40220, 38043 Grenoble Cedex 9, France

3 SOLEIL Synchrotron, DiffAbs beam-line, L‘Orme des Merisiers, Saint-Au-bin - BP 48, 91192 Gif-sur-Yvette Cedex, France

[email protected]

Talk

Dr. Thomas Cornelius

In situ synchrotron X-ray diffraction techniques

In recent years, synchrotron X-ray techniques progressed tremen-dously thanks to the increase of the brilliance of 3rd generation synchrotron sources as well as the achieved improvements re-garding focusing optics rendering possible to focus hard X-ray beams down to the 100 nm scale. These highly brilliant and highly focused hard X-ray beams allow for following in situ the evolution of nanostructures for studying their properties. Togeth-er with the brilliance the coherence of the incident X-ray beams was increased as well triggering the development of a new lens-less imaging method – Bragg coherent diffraction imaging. This new technique facilitates the measurement of strain in individual nanostructures with unprecedented precision [1-2]. While most measurements concentrated on weakly deformed objects under “static” conditions, recent developments aim on imaging defects as well as the strain field in nanostructures in operando [3] and during nano-indentation. The recent achievements on in situ X-ray studies will be illustrated by nano-mechanical and local piezo-electric measurements employing dedicated instruments recently developed in our group at IM2NP in Marseille [4-5].

[1] S. Labat, M.-I. Richard, M. Dupraz, M. Gailhanou, G. Beutier, M. Verdier, F. Mastropietro, T.W. Cornelius, T.U. Schülli, J. Eymery, O. Thomas, ACS Nano 9 (2015) 9210.[2] M.C. Newton, S.J. Leake, R. Harder, I.K. Robinson, Nature Materials 9 (2010) 120.[3] A. Ulvestad, J.N. Clark, A. Singer, D. Vine, H.M. Cho, R. Harder, Y.S. Meng, O.G. Shpyrko, Phys. Chem. Chem. Phys. 17 (2015) 10551.[4] C. Leclere, T.W. Cornelius, Z. Ren, A. Davydok, J.-S. Micha, O. Robach, G. Richter, L. Belliard, O. Thomas, J. Appl. Cryst. 48 (2015) 291. [5] A. Davydok, T.W. Cornelius, C. Mocuta, E.C. Lima, E.B. Araùjo, O. Thomas, Thin Solid Films 603 (2016) 29 – 33

26

Jürgen Kraus 1, Robert Reichelt1, Sebastian Günther1, Luca Gregoratti2, Matteo Amati2, Maya Kiskinova2, Alexander Yulaev3, Andrei Kolmakov3

1 Technical University of Munich, Catalysis Research Center and Chemistry Department, Associate Professorship of Physical Chemistry with Focus on Catalysis, Lichten-bergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

2 Sincrotrone Trieste, Area Science Park, 34149 Trieste - Basovizza, Italy

3 Center for Nanoscale Science and Technology, NIST, Gaithersburg, MD 20899, USA

[email protected]

Talk

Jürgen Kraus

Graphene membranes as electron transparent windows for photoelectron spectroscopy

Ultrathin membranes are of great interest for applications where gases or liquids should be enclosed in a small volume to introduce them into UHV systems and investigate them by means of electron spectroscopy. Monolayer graphene (MLG) combines a minimum thickness with high mechanical stability which makes it the ideal material for the fabrication of such ultrathin membranes.

Therefore, MLG films were grown by chemical vapor deposition on copper foils. By locally etching the Cu-substrate underneath the as-grown graphene, free standing graphene membranes could be fabricated. We measured the transparency of the CVD-grown graphene for low kinetic energy photoelectrons in the energy range of 200-1400 eV showing a high transmission between 50 % and 80 %. In order to determine the sensitivity of this technique, gold was deposited on one side of the graphene membranes and the Au 4f photoelectron signal was collected through the graphene membrane which proved that < 1% of a monolayer Au can be de-tected. This opens up many applications of suspended graphene membranes for the surface characterization by photoelectron spectroscopy under ambient conditions.

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Schwarz Martin1, Garnica Manuela2, Stradi Daniele3, Barth Johannes V.2, and Auwärter Willi1



3 Department of Micro- and Nano-technology, Center for Nanostructu-red Graphene, Technical University of Denmark, Denmark

[email protected]

Talk

Martin Schwarz

Catalytic role of metal substrates for the growth of hexagonal boron nitride

Ultrathin films of hexagonal boron nitride (h-BN) have attracted considerable interest in recent years due to their integration in graphene-based nano-electronic devices and their use as spacer layers to electronically decouple and order functional adsorbates. The successful growth of single BN layers by chemical vapor deposition (CVD) or subsequent chemical reactions has been re-ported on various transition metals.

Here, we introduce an h-BN monolayer grown on a copper single crystal, representing a model system for an electronically pat-terned but topographically smooth substrate [1]. Furthermore we explored different synthesis methods of boron nitride layers on silver substrates. Beside the direct growth of h-BN on Ag(111), silver intercalation on the h-BN/Cu(111) system was investigated.

The quality of the resulting layers has been examined by high-reso-lution scanning tunneling microscopy while the electronic structure of the metal surfaces upon 2D layer growth has been studied by scanning tunneling spectroscopy and complementary first-prin-ciple calculations. We demonstrate that the adsorption of the 2D layer preserves the insulating character of bulk hexagonal boron nitride but alters the substrate’s surface potential and has an im-pact on the binding energy of the Shockley-state. It is shown that the catalytic metal substrates play a crucial role in the decompos-ition of the borazine precursor gas. The h-BN sheets are used to create metal-organic networks featuring structural, electronic and magnetic properties unachievable on metallic supports [2].

[1] Joshi, S. et. al., Nano Lett., 2012, 12, 5821-5828. [2] Urgel, J. I., et. al., J. Am. Chem. Soc., 2015, 137 (7), 2420.

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Keynote

Dr. Martin Strassburg

LEDs and laser diodes: Today’s and future trends in lighting

Semiconductor based light emitting diodes (LEDs) and laser di-odes (LDs) paved the way for novel developments in the general illumination sector in the recent years, similar to the semicon-ductor triggered electronic revolution some decades ago. They are compact in size and can be made very robust to be used in various application fields supported by their long lifetimes. They have demonstrated superior efficiency for almost every field of application compared to incandescent and conventional lighting technologies, from low-power (e.g., signaging) to high power applications (e.g. projection). Today, lighting is by far more than brightness and efficiency. Other properties of light have gained increasing importance strongly triggered by the human perception of light, such as correlated color temperatures, brilliance and color rendering index. In addition, the convergence of photonics and electronics yields technological integration and miniaturization of LEDs enabling novel functionalities, steering routines and indivi-dual configurations.

An introduction to OSRAM Opto Semiconductors’ numerous activities in research and development of next generation LEDs/ Lasers and future trends for lighting applications will be given. Examples such as high power LEDs and pixelized LEDs will illus-trate the close interplay of material development, thorough under-standing of scientific background and of technological solutions yielding to products keeping the leadership in many application fields.

osram-os.com

OSRAM Opto Semicondutors GmbH, Leibnizstr. 4, 93055 Regensburg, Germany

[email protected]

29

Kai E. Sanwald1, Tobias F. Berto1, Wolfgang Eisenreich1, Oliver Y. Gutiérrez1, Johannes A. Lercher1


[email protected]

Kai Sanwald

Catalytic routes and oxidation mechanisms in photorefor-ming of oxygenates

Photocatalytic reforming of biomass-derived oxygenates is as a promising route to carbon-neutral H2. The technology may pro-vide simpler pathways compared to overall water splitting, as the recombination of H2 and O2 is avoided and separation is greatly facilitated. The wide abundance of oxygenate contaminants in water would make this even a preferred route, coupling water cleaning with storing photon energy in H2.

We probed photoreforming of polyols and sugars over a bench-mark Rh/TiO2 photocatalyst to identify the nature and kinetics of transformations of reactants, intermediates, and elementary steps. Anodic oxidation of oxygenates proceeds via direct and indirect hole transfer mainly resulting in (i) oxidative rupture of C-C bonds, and (ii) oxidation to aldoses or ketoses while evolving H2 at the cathode. We establish that the molecular reactant structure has a periodic impact on the contribution of those oxidation mechan-isms, and photocatalytic rates. Increasing conversion of polyols via direct C-C-cleavage in the first step with increasing chain length result from the increasing number of anchoring OH-functionalities favoring conversion through a direct hole transfer mechanism. Photocatalytic rates of linear C1-C3 oxygenates are primarily de-pendent on the substrate specific apparent adsorption constants and follow a Langmuir adsorption model. On the other hand, declines in H2-evolution rates over time beyond this model are encountered in the presence of cyclic hemiacetals and formates derived therefrom, which is a consequence of blocking of anodic sites by formate species while the cathodic half-reaction does not limit to the overall photocatalytic rates under these conditions. This contribution highlights the importance of the understanding of the surface chemistry in photocatalytic transformations of struc-turally complex feeds.

[1] K. Shimura, H. Yoshida, Energ. Environ. Sci. 4 (2011) 2467-2481. [2] .T.F. Berto, K.E. Sanwald, W. Eisenreich, O.Y. Gutiérrez, J.A. Lercher, J. Catal. 2016, 338, 68-81. [3] R. Chong, J. Li, Y. Ma, B. Zhang, H. Han, C. Li, J. Catal. 2014, 314, 101-108.

Talk

30

Anthoula C. Papageorgiou1, Alissa Wiengarten1, Katharina Diller1, Sybille Fischer1, Seung Cheol Oh1, Özge Saglam1, Julian A. Lloyd1, Knud Seufert1, David A. Duncan1, Manuela Garnica1, Joachim Reichert1, Francesco Allegretti1, Florian Klappenberger1, Willi Auwärter2, Johannes V. Barth1



[email protected]

Dr. Anthoula Papageorgiou

Metallo-porphyrin chemistry on surfaces

Metal-organic species and nanoarchitectures at well-defined inter-faces provide high potential for key technological applications, spanning over the design of single-site heterogeneous catalysts, novel materials for light harvesting, the fabrication of molecular rotors and nanomachines and the advent of molecular spintronics. The advancement is underpinned by the continuous development of materials with tailored properties controllable at the molecular scale. Thus it is of central importance to explore new strategies for synthesis and processing, which should ideally minimize costs and effort and be clean, reproducible and highly controlled.

Tetrapyrrole molecules and in particular porphyrins are stable, nat-urally occurring compounds which can coordinate a vast array of metal centres [1]. Here we visit the chemical transformations that prototypical porphyrin species, such as tetra phenyl porphyrin [2] and porphine [3], undergo upon thermal tr eatment on a silver surface. In particular, we exemplify stereo and chemo-selectivity in both intramolecular and intermolecular dehydrogenative reactions which result in an extension of the conjugated molecular system. We further investigate the on-surface functionalization of such species with various metals, including Ru [4] and Os [5].

Our methodology encompasses a battery of cutting-edge ex-perimental techniques developed for ultrahigh vacuum surface science: scanning probe microscopies address single molecule behaviour, while temperature programmed reaction spectroscopy, photoelectron spectroscopy and near edge X-ray absorption fine structure allow to scrutinize molecular ensembles. The integra-tion of all these analysis techniques combined with theoretical considerations generates a high degree of precision in the under-standing of interfacial reactions at the atomic level. Henceforth the structure function relationships of the reactions may be deciphered enabling inno vative pathways for the bottom-up fabrication of advanced, functional nanoarchitectures.

[1] Diller, K., et al. Chem. Soc. Rev. 2016, 45, 1629-1656. [2]. Wiengarten, A., et al. Chem. Eur. J. 2015, 21, 12285-12290. [3] Wiengarten, A., et al. J. Am. Chem. Soc. 2014, 136, 9346-9354.[4] Papageorgiou, A. C., et al. ACS Nano 2013, 7, 4520-4526.[5] Saglam, Ö., et al. Surf. Sci. 2016, 646, 26-30.

Talk

31

Kaspar Manuel1, Corinna Hess1

1 Technical University of Munich, Catalysis Research Center and Chemistry Department, Assistant Professorship of Bioinorganic Chemistry, Lichtenbergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Talk

Manuel Kaspar

Synthesis, characterization and reactivity of a series of Co(Mabiq) complexes

So far, the reduction of protons is sufficiently fast only on rare and expensive noble metal electrodes. However, current research fo-cuses on the development of catalysts using abundant and cheap metals to replace noble metals [1]. Over the past years, macro-cyclic cobalt complexes have arisen as encouraging systems for water splitting and proton reduction [2]. For the design of new catalytic systems, one has to consider that the reduction of water is a two electron process and that biological systems often use redox-active ligands for multi-electron processes [3].

Therefore, we were interested in the bioinspired redox-active macrocyclic N4 ligand (Mabiq), which supports formal metal va-lences from 0 to +3. We have synthesized a series of Co(Mabiq) complexes and succeeded in isolating the formally Co(III), Co(II), Co(I) forms and another low-valent compound. The complexes have been characterized by means of different spectroscopic methods, as well as by magnetic susceptibility studies. Electro-chemical and reactivity studies indicate activity of the Co(Mabiq) system with respect to hydrogen evolution.

[1] Mahammed, A.; Mondal, B.; Rana, A.; Dey, A.; Gross, Z., Chem. Commun. 2014, 50, 2725. [2] Artero, V.; Chavarot-Kerlidou, M.; Fontecave, M., Angew. Chem. Int. Ed. 2011, 50, 7238-7266. [3] Jurss, J. W.; Khnayzer, R. S.; Panetier, J. A.; El Roz, K. A.; Nichols, E. M.; Head-Gordon, M.; Long, J. R.;Castellano, F. N.; Chang, C. J., Chemical Science 2015, 6, 4954-4972.

32

Ruth Haas1, Corinna Hess

1 Technical University of Munich, Catalysis Research Center and Chemistry Department, Assistant Professorship of Bioinorganic Chemistry, Lichtenbergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Talk

Ruth Haas

Asymmetric bimetallic complexes for multi-electron catalysis

Non-innocent ligands, such as diimine or PDI (pyridine diimine) scaffolds, are generating a platform of catalytically active com-plexes for small molecule activation. These scaffolds can store up to three electrons [1] and therefore support metal complexes with varied charged states. Several examples of metal complexes containing non-innocent ligands are already known and have been used for oxidation, hydrogenation [2] and polymerisation reactions [3].

We have incorporated redox-active ligands into the design of our new asymmetric bimetallic complexes. The ligand scaffold con-tains two coordination sites, a PDI group adjacent to a cyclam ring, bridged by an aliphatic chain. The idea behind our design is that the synergistic interactions of the metal might facilitate multi-electron reactions and mimic enzyme activities.

A goal of our studies will be now to catalyse small molecule chem-istry including like hydrogen production and CO2 activation. The complexation chemistry of the ligands was studied and suggests the formation of bimetallic compounds, which were examined by spectroscopic and electrochemical methods. Results of these studies and preliminary reactivity studies will be presented.

[1] S. C. Bart, K. Chłopek, E. Bill, M. W. Bouwkamp, E. Lobkovsky, F. Neese, K. Wieghardt, P. J. Chirik, J. Am. Chem. Soc. 2006, 128, 13901–13912. [2] P. J. Chirik Acc. Chem. Res. 2015, 48, 1687−1695. [3] M. W. Bouwkamp, E. Lobkovsky, P. J. Chirik J. Am. Chem. Soc. 2005, 127, 9660-9661.

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Institute of Computational Chemistry and Catalysis (IQCC) and Departament de Quimica, Universitat de Girona, Spain

[email protected]

Keynote

Prof. Miquel Costas

Selective oxidation reactions with bioinspired catalysts

Biologically inspired catalysts are explored in our research efforts with the aim to produce selective oxidation reactions. The quest for catalytic methodologies that provide novel reactivities and selectivities that could complement those attained with traditio-nal oxidants, or that could represent a more efficient alternative constitute major reasons of interest for this approach [1].

Towards this end, iron coordination complexes ligated to amine and oxygen containing functionalities, and that could be viewed as a minimalistic model of iron coordination sites in nonheme iron de-pendent oxygenases, are employed as catalysts for the oxidation of organic substrates. By control of their structure and electronic properties, catalysts have been designed by our research team that engage in controlled O-O lysis of H2O2 to form highly electro-philic high valent metal-oxo species that are finally responsible for enzyme-like selective oxidation chemistry [2-4].

Principles of catalyst design and use of these catalysts in selective C-H and C=C oxidation reactions as well as efforts aiming at the Identification of reaction intermediates [5] responsible for these oxidations will be discussed.

[1] L. Que, W. B. Tolman, Nature 2008, 455, 333 [2] Z. Codola, J. Lloret-Fillol, M. Costas, in Progress in Inorganic Chemistry: Volume 59, John Wiley & Sons, Inc., 2014, pp. 447-532. [3] O. Cussó, X. Ribas, J. Lloret-Fillol, M. Costas, Angew. Chem. Int. Ed. 2015, 54, 2729-2733. [4] O. Cussó, M. Cianfanelli, X. Ribas, B. Klein Gebbink, M. Costas, J. Am. Chem. Soc. 2016, 138(8), 2732–2738. [5] J. Serrano-Plana, W Oloo, L. Acosta-Rueda, K. Meier, B. Verdejo, E. Garcia-España, M. Basallote, E. Münck, L. Que, A. Company, M. Costas, J. Am. Chem. Soc. 2015, 137(50), 15833–15842.

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Posters

36

Johannes D. Bartl1,2, Christian M. Wolff3, Marian D. Rötzer1, Markus Döblinger4, Florian F. Schweinberger1, Jochen Feldmann3, Ueli Heiz1

Johannes Bartl

High-performance photocatalytic hydrogen evolution on size-range selected Ni-cluster decorated CdS nanorods

Addressing the overall limitation of fossil energy carriers and noble metals, a noble-metal-free photocatalytic system using Ni clusters for highly efficient hydrogen evolution as a renewable energy source has been developed. Well-established nuclea-tion and growth processes of metal clusters on semiconductor photocatalysis are based on either light-assisted deposition [1] or chemical reduction [2] of oxidized precursors in solution, however lack independent control of cluster size and coverage. To this end, recently a new photocatalytic hybrid material based on CdS na-norods (NRs) decorated with metal clusters has been introduced. By means of catalyst deposition from a laser ablation cluster source under ultra-high vacuum conditions independent control of coverage and size of the co-catalyst could be established [3,4].

In this work size-range selected Ni clusters deposited on CdS nanorods (NRs) in a highly alkaline environment are presented as high-performance photocatalysis. The three-component system consists of CdS NRs as a photosensitizer, EtOH as a sacrificial electron donor and Ni as a co-catalyst. This allows on one hand for an atomic scale insight into a photocatalytic system, by utilizing sub nanometer clusters as tailored catalyst materials. On the other hand, by independently controlling the number of clusters per CdS NR’s unit area together with highly optimized reaction conditions exploiting the redox shuttle mechanism [5] a potent new hybrid photocatalytic system is created. Considering the lower costs of earth-abundant metals this novel platform promotes an overall efficiency of four orders of magnitude higher than comparable noble-metal based photocatalytic systems [3,4].

[1] Berr, M. J. et al., Small 8, 291–297 (2012).[2] Habas, S. E. et al., J. Am. Chem. Soc. 130, 3294–5 (2008).[3] Schweinberger, F.F. et al., J. Am. Chem. Soc. 135, 13262– 13265 (2013).[4] Berr, M. J. et al., Nano Lett. 12, 5903–5906 (2012).[5] Simon, T. et al., Nat. Mater. 13, 1013–1018 (2014).

Poster

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Physical Chemistry, Lichtenbergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

2munich marseille graduate school of nanoscience (m2gsn), Master Nanoscience and Catalysis m2gsn.tum.de

3Ludwig-Maximilians-Universität München, Photonics and Optoelec-tronics Group, Department of Physics and Center for NanoScience (CeNS), Amalienstraße 54, 80799 München, Germany

4Ludwig-Maximilians-Universität München, Department of Chemistry, Butenandtstraße 5-13 (E), 81377 München, Germany

[email protected]

37

Poster

Christoph Brenninger1, Thorsten Bach1

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Organic Chemistry 1, Lichtenbergstra-ße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Christoph Brenninger

Sulfonium ions in organic photochemistry

The [2+2] photocycloaddition is one of the most important and most frequently used photochemical transformations and had also a large impact on natural product synthesis.[1] In this type of reaction two π-bonds are used to obtain two new σ-bonds and up to four stereogenic centres are set up. Due to its large number of stereogenic centres and fast access to cyclobutanes and their consecutive reaction products enantioselective methods are desirable [1,2]. Therefore different enantioselective methods using auxiliary based approaches, PET (photoinduced electron transfer) catalysis, excitation via sensitization and Lewis acid cat-alysis were investigated [2]. Enantioselective intramolecular [2+2] photocycloaddition reactions of enones are difficult due to their unselective background reactions via ππ* excitation and therefore high catalyst loadings are necessary [3,4].

In this project the effect of acetalization and thioacetalization of enones on their photo physical properties were studied. Due to this modifications ππ* transitions are no longer observable and ππ* transitions are shifted to shorter wavelengths, comparable to those of isolated double bonds. As expected from their UV/Vis spectra dioxalanes, dithiols and dithianes undergo no unselect-ive background reactions, since there is no absorption between 250 nm and 400 nm. Formation of oxonium and sulfonium ions by Brønsted acids leads to absorptions at 280 nm and 356 nm, which can be used for photochemical reactions at 300 nm and 405 nm respectively. Racemic intramolecular [2+2] photocycloaddition reactions were carried out with 7.5 mol% of catalyst. Chiral Brøn-sted acids might allow an enantioselective reaction, which is also under investigation [5].

[1] T. Bach, J. P. Hehn, Angew. Chem. Int. Ed. 2011, 50, 1000-1045.[2] S. Poplata, A. Tröster, Y.-Q. Zou, Thorsten Bach, Chem. Rev. ASAP.[3] R. Brimioulle, T. Bach, Science 2013, 342, 840-843.[4] R. Brimioulle, T. Bach, Angew. Chem. Int. Ed. 2014, 53, 12921-12924.[5] R. J. Phipps, G. L. Hamilton, F. D. Toste, Nat. Chem. 2012, 4, 603-614.

38

Courtois Carla1,2, Lukas Niederegger1, Michael Röpke1, Radka Kittova1, Friedrich Esch1

Carla Courtois

Light scattering on electrophoretic inks of carbon and TiO2 particles

Electrophoretic ink displays are nowadays used in many paper-like devices, nevertheless not many open-source research information about electrophoretic displays are available since the commer-cialization of E-Readers. Based on the research of Werts et al., we constructed an e-ink display cell. An image is produced by applying an external electric field between a copper plate and indium-tin-oxide (ITO) glass in which charged particles can align. These particles reside between those two plates in a dielectric suspension. For the purpose of getting a high contrast, white TiO2

particles and black functionalized carbon particles were charged with polyisobutylene succinimide (OLOA 1200) [1].

Building of an e-ink cell requires measurement of the scattered light to determine the contrast and the switching time. The reflec-tivity of a HeNe-laser on a prepared e-ink cell was measured by a Si photodiode. In order to reduce the noise, a resistance was added to the photodiode and the data acquisition was optimized in a self-made LabVIEW program. The sensitivity of the photodiode turned out to be higher using a brighter suspension; thus a higher ratio of white TiO2 to black carbon particles was applied so that an appropriate switching was measured. Finally, the setup was improved so that a difference between black and white particles results in 120 mV and the characteristics of the e-inks such as the switching time and contrast were investigated.

[1] M. P. L. Werts et al., Chem. Mater. 20, 1292-1298 (2008).

Poster



[email protected]

39

Poster

Konstantin Epp1, Mirza Cokoja1, Christoph Rösler1, Stefano Disseg-na1, Francesc X. Llabrés i Xamena2, Roland A. Fischer1

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Inorganic and Organometallic Chemis-try, Lichtenbergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

2Instituto de Tecnología Química, Consejo Superior de Investigaciones Científicas, Universidad Politécnica de Valencia, Spain

[email protected]

Konstantin Epp

Metals@MOFs and defect engineering as methods for catalysts optimization

Metal-Organic Frameworks (MOFs) are materials which are formed by a self-assembly of inorganic secondary building units (SBU) connected by multitopic organic linkers. Like zeolites MOFs prom-ise catalysis-friendly features such as large internal surface areas, extensive micro- and/or mesoporosity, and crystallographically well-defined cavities and portals of molecular dimensions, which makes them attractive as potential heterogeneous catalysts [1]. Nowadays catalysts need to satisfy requirements such as sus-tainability, recyclability and also face challenges like insufficient selectivity.

Therefore, we report on multi-functional catalyst design, f.e. the controlled encapsulation of atom-precise clusters (Co, Mo etc.) and nanoparticles (NP) into MOFs, abbreviated as metal@MOFs (Pd, Cu, Au etc.) and discuss the catalytic properties [2]. This con-cept could be extended to core/shell metal NP (f.e. Pd@Pt) in order to introduce novel centers of reactivity and also take advantage of the size-selective catalysis of substrates induced by the given pore-diameter [3]. As another concept, we report defect engineer-ing as a synthetic tool for node-functionalization at the metal-oxo clusters of the SBU, generating structural defects (in particularly coordinatively unsaturated sites) which trigger enhanced reactivity and engender catalyst design on an atomistic level in the isomer-ization/ hydrogenation of olefins [4].

[1] H. Li, M. Eddaoudi, M. O‘Keeffe, O. M. Yaghi, Nature 1999, 402, 276-279.[2] S. Hermes, Roland A. Fischer et al. Angew. Chem. Int. Ed. 2005, 44, 6237 –6241.[3] I. Luz, C. Rösler, K. Epp, F. X. Llabrés i Xamena, Roland A. Fischer, Eur. J. Inorg. Chem. 2015, 3904–3912.[4] O. Kozachuk, I. Luz, F. X. Llabrés i Xamena, H. Noei, M. Kauer, H. B. Albada, E. D. Bloch, B. Marler, Y. Wang, M. Muhler, R. A. Fischer, Angew. Chem. Int. Ed. 2014, 53, 7058-7062.

40

Stefan Ewald1, Kai-Olaf Hinrichsen1

Stefan Ewald

On the surface determination of a coprecipitated Ni/Al2O3 catalyst by chemisorption of N2O and H2

For the characterization of Ni surfaces H2-TPD and static H2 chemi-sorption are widely used [1-2]. Recently Tada et al. established the pulse titration of N2O to determine the Ni surface area of impreg-nated Ni/α-Al2O3 catalysts [4]. In this contribution N2O chemisorp-tion for Ni surface area determination of a coprecipitated Ni/Al2O3

catalyst is compared with static H2 chemisorption and H2 TPD.

The catalyst is prepared via coprecipitation of the corresponding metal nitrate salts. The precipitate is calcined at 723 K and ana-lyzed by static H2 chemisorption. N2O chemisorption and H2-TPD are conducted in a flow setup. H2 adsorption prior to H2 TPD is either conducted by injecting diluted H2 into a He stream flowing over the catalyst or by feeding non diluted H2 gas into the reactor. N2O chemisorption is either conducted as flow experiment or as titration experiment using N2O pulses flowing over the catalyst.

The Ni surface area of 16.6 m2/gcat after adsorption of 40 H2 puls-es agrees well with 17.1 m2/gcat from static H2 chemisorption. In contrast, the Ni surface area is 24.6 m2/gcat when adsorbing H2 for 30 min. N2O chemisorption gives a Ni surface area of 65,1 m2/gcat which is higher than results from static H2 chemisorption and H2-TPD. N2O titration experiments still give a significantly higher Ni surface area. N2O chemisorption seems to overestimate the Ni surface area of the catalyst studied. It is currently under investi-gation to what extent the catalyst support and synthesis influence N2O chemisorption results.

[1] L. Znak, J. Zielinski, Appl. Catal. A, 334 (2008) 268-276.[2] S. Velu, S.K. Gangwal, Solid State Ionics, 177 (2006) 803-811.[3] R. Geyer, J. Hunold, M. Keck, P. Kraak, A. Pachulski, R. Schödel, Chem. Ing. Tech. 84 (2012)[4] S. Tada, M. Yokoyama, R. Kikuchi, T. Haneda, H. Kameyama, J. Phys. Chem. C, 117 (2013) 14652-14658.

Poster


[email protected]

41

Poster

Steffen Garbe1,2, Marvin Lechner1, Jakob Filser1, Friedrich Esch1



[email protected]

Steffen Garbe

Intensity and wavelength dependence of a dye-sensitized solar cell

The control and improvement of electricity gaining solar devices is of great importance in emerging renewable energy technologies. Commonly established solar cells are built out of semiconducting materials on the basis of silicon to convert sunlight into energy.

Nanocrystalline dye-sensitized solar cells represent a promising different technology, orientated at the two-step photosynthetic pro-cess in plants, i.e. excitation of an organic dye by electromagnetic radiation in the UV/Vis range and deexcitation by electron transfer into the conduction band of the semiconductor. Dye-sensitized solar cells can be produced using natural anthocyanin dyes ex-tracted from berries, titanium dioxide as semiconductor and iodide electrolyte solution. However, further improvements concerning efficiency performance and fill factor are essential for commer-cialization. The efficiency performance is mainly dependent on the integrated materials, whereas non-ideal conditions caused by parasitic effects decrease the power maximum and therefore the fill factor. Determination and reduction of these effects pave the way towards high-power dye-sensitized solar cells.

We report the construction of the cell, the acquisition of data and the specific properties of the cell. The results of the experiments show increasing power at higher radiation intensities, wavelength dependency and lead to further investigations concerning the ef-ficiency improvement.

[1] A. D. Dhass et al., 2012 International Conference on ICETEEEM, pp. 382–386 (2012).[2] Greg P. Smestad et al., Journal of Chemical Education 75 752 (1998).

42

A. De Clercq1, L. Piccollo2, S. Giorgio1

Prof. Suzanne Giorgio

In situ study of Au-Rh Nanoalloys, growth in solution and reactivity

Au-Rh nanoalloys prepared from colloidal solution [1], were in situ studied in a graphene liquid cell [2-3] and in an environment-al sample holder [4], by transmission electron microscopy. The growth mechanism in liquid was initiated under the electron beam, the size and density number of NPs was recorded in the same area during the nucleation and growth process. The density number indicates a maximum after 25 s, then a drop after 50 s in the elec-tron beam, corresponding to a mechanism by direct adsorption of the monomers followed by coalescence of the particles. The effect of oxidation- reduction cycles on the structure and morphology of Au-Rh nanoparticles supported on TiO2 nanorods powders, was in situ followed by ETEM.

In the largest NPs, core- shell formation was clearly observed during hydrogen adsorption. On the other hand, the observation of Au-Rh NPs annealed ex situ in H2 at 400 °C, also shows the core- shell contrast which was not visible before H2 treatment. The strong interaction between hydrogen and Rh is certainly respon-sible for the surface segregation of Rh.

We thank the ANR DINAMIC11BS10-009 for financial support and Région PACA for a grant given for the PhD thesis of A. De Clercq (2012-2015).

[1] Konuspayeva et al., PCCP 17 (2015) 28122.[2] J.M. Yuk et al., Science, 336 (2012) 61.[3] De Clercq, et al., J. Phys. Chem Lett., 5 (2014) 2126-2130.[4] S. Giorgio et al., Ultramicroscopy. 106 (2006) 503.

Poster

1CINAM, Aix Marseille Université, CNRS, CINaM UMR 7325 Marseille France.

2IRCELYON, CNRS, Villeurbanne, France.

[email protected]

43

Poster

Tobias F. Berto1, Kai E. Sanwald1, Oliver Y. Gutiérrez1, Johannes A. Lercher1


[email protected]

Dr. Oliver Gutiérrez

Overall water splitting over photocatalysts with CO-covered noble metals

Photocatalytic overall water splitting requires co-catalysts, which efficiently promote the generation of H2 but do not catalyze its back reaction with O2 to water. We demonstrate, that CO chemisorbed on precious metal co-catalysts (Rh, Pt, Pd) suppresses the back reaction while preserving the H2 evolution reaction (HER). Over Rh/GaN:ZnO, maximum H2 production rates are obtained between 4 and 40 mbar of CO while the back reaction is suppressed below 7 mbar of O2. The O2 evolution reaction (OER) and HER compete with CO oxidation and a light-driven back reaction, re-spectively. The rates of all these reactions rise with increasing photon absorp-tion. However, due to different dependences on the rate of charge carrier generation, the selectivities to OER and HER increase over CO oxidation and back reaction with increasing photon flux and/or quantum efficiency. Under optimum conditions, the efficiency of the CO molecular layer (manipulable by CO partial pressure, photon flux, and quantum efficiency of the photocatalyst) for hin-dering the back reaction is identical to the effect of a Cr2O3 layer covering the HER-active core.

44

Han Li1, Fritz E. Kühn1

Han Li

Synthesis of new Fe-NHC complexes and corresponding exploration of their photo properties

More and more attention has been drawn on the chemical utiliza-tion of solar energy in recent years. A range of sensitizers emerged over these years, while the Ru and Ir complexes remain to be the most widely utilized photocatalysts. Meanwhile, great efforts have been made to replace the rare elements complex with the earth abundant elements such as Fe.

Unfortunately, little progress was achieved due to the extremely short-lived metal-to-ligand charge transfer states of iron complex-es. However, a big breakthrough has been made recently, which demonstrated that some iron complex bearing NHCs was able to converts light to electrons with 92% yield.This throws highlight on further research of exploring Fe complexes as new visible light catalysts.

On this occasion, we plan to synthesis iron complex with new structure, and explore its photo properties, aiming at making some progress towards the utilization of Fe complex in photocatalysis.

[1] Eur. J. Inorg. Chem., 2015, 2469.[2] Inorg. Chem. 2015, 560.[3] Nat. Chem. 2015, 883.[4] NPG Asia Materials, 2016, e261.

Poster

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Associate Professorship of Molecular Catalysis, Lichtenbergstraße 4 and Ernst-Ot-to-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

45

Poster

Alena Hölzl1, Thorsten Bach1

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Organic Chemistry 1, Lichtenbergstra-ße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Alena Hölzl

Enantioselective photoreactions of diazocompounds using a chiral thioxanthone catalyst

One of the major challenges in photochemistry is the utilization of visible light for enantioselective transformations. Having suit-able sensitizers in hand visible light can be used for excitation, similar or even more effective than UV-light. In 2014 Bach et al. presented a chiral thioxanthon catalyst [(-)-TX] for enantioselective [2+2] photocycloaddition reactions induced by visible light [1]. To further utilize this highly promising catalyst the identification of new substrate classes is required. A special binding motif for the substrates is necessary promoting a chiral environment by non-covalent interactions between the substrate and catalyst.

Diazocompounds are an interesting substance class due to their ability to form triplet carbenes after photochemical excitation using a sensitizer [2-3]. Preliminary work by A. V. Silva showed the reactivity of different diazocompounds towards alkenes and alkynes after photochemical excitation. Irradiation (λ = 419 nm) of the diazocompound 3-diazopiperidin-2-one and an alkyne in presence of the (-)-TX catalyst promotes the formation of an allene. The enantioselective reaction could be performed with excellent ee`s from 96% to 99% with yields up to 41%. The formation of the allene was proved by deuterium experiments. To further optimize the yields different reaction conditions will be screened and the substrate scope will be extended.

[1] R. Alonso, T. Bach, Angew. Chem. Int. Ed. 2014, 53, 4368-4371.[2] J. P. Toscano, M. S. Platz, V. Nikolaev, V. Popic, J. Am. Chem. Soc. 1994, 116, 8146-8151.[3] H. D. Roth, M. L. Manion, J. Am. Chem. Soc. 1975, 97, 779-783.

46

Benjamin J. Hofmann1, Jens W. Kück1, Fritz E. Kühn1

Benjamin Hofmann

Lignin as renewable carbon feedstock - Studies on the cleavage of a β-O-4 model substrate by Re2O7

Lignin is a promising renewable carbon feedstock due to its high abundance and highly aromatic structure. For an application, low molecular weight compounds have to be obtained by the selective degradation of the macromolecular structure. For this purpose, redox active catalysts as well as acids or bases are mainly applied, although photocatalytic systems are also known in the literature [1-2].

In this work, the Lewis acid Re2O7 is applied in the cleavage of the most abundant β-O-4 binding motif. Using 2-(2-methoxyphenox-y)-1-phenylethanol as a model substrate, full conversion is ob-tained within 7 h (TOF 240 h–1) using low catalyst concentrations of 0.1 mol% (TON >800). Conveniently, a good selectivity towards guaiacol and phenyl acetaldehyde is observed with 75 – 80 %. Detailed kinetic studies reveal the formation of different by-prod-ucts depending on the reaction progress. In contrast to MTO, a reduction step is no prerequisite for the formation of the active species.[3] UV/Vis experiments at low temperatures suggest the participation of nanoparticles in the early stage of the reaction.

[1] L. J. Mitchell, C. J. Moody, The Journal of Organic Chemistry 2014, 79, 11091-11100.[2] J. D. Nguyen, B. S. Matsuura, C. R. J. Stephenson, J. Am. Chem. Soc. 2014, 136, 1218-1221.[3] R. G. Harms, I. I. E. Markovits, M. Drees, W. A. Herrmann, M. Cokoja, F. E. Kühn, ChemSusChem 2014, 7, 429-434.

Poster

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Associate Professorship of Molecular Catalysis, Lichtenbergstraße 4 and Ernst-Ot-to-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

47

Poster

J. Hornung1, H. Banh1, J. Wessing1, K. Dilchert1, K. Freitag1, M. Cokoja1, C. Gemel1, R. A. Fischer1

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Inorganic and Organometallic Chemis-try, Lichtenbergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Julius Hornung

Intermetallic clusters and nanoalloys and their applications for catalysis

During the last years a lot of effort has been made to successfully synthesize a huge variety of molecular intermetallic compounds. This research is based on the coordination chemistry of ER (E = Al,Ga,In, R=Cp*) and MR’ (M = Zn, Cd, R = Cp*, Me) and led to the synthesis of [Mo(ZnCp*)3(ZnMe)9][1], [Ni(ZnCp*)a(ZnMe)a (PMe3)4-a](a = 1, 2, 4) [2] and [(CuAlCp*)6H4] [3]. These compounds are not only interesting in terms of their conceptual bond de-scriptions but also as molecular models for surface reactions at intermetallic catalysts and precursors for nanoalloy synthesis. Especially, the preparation of Ru/Ga [4], Cu/Zn [5], Ni/Ga [6], and Fe/Al nanoalloys is under investigation for their potential applications as catalysts for industrially relevant hydrogenation reactions. A molecular model for surface reactions is the 1:1 in-sertion product [(CuAlCp*)6H3(N=CHPh)] that was isolated after reaction of [(CuAlCp*)6H4] with benzonitrile [3]. In this context, the compounds [Ni(ZnCp*)a(ZnMe)a(PMe3)4-a] are also examined as molecular congeners of catalytically relevant NiZn alloys. In general, our concept is to transfer our knowledge and use the above described molecular chemistry of clusters, mimicking struc-tural cut-outs of Hume-Rothery type intermetallics, for applications in catalysis.

[1] T. Cadenbach, T. Bollermann, C. Gemel, M. Tombul, I. Fernandez, M. v. Hopffgarten, G. Frenking, R. A. Fischer, J. Am. Chem. Soc. 2009, 131, 16063-16077.[2] M. Molon, Dissertation, RUB, 2013; „Metallatomreiche Koordinationsverbindungen“[3] C. Ganesamoorthy, J. Wessing, C. Kroll, R. W. Seidel, C. Gemel, R. A. Fischer, Angew. Chem. Int. Ed. 2014, 53, 7943-7947.[4] T. Cadenbach, C. Gemel, R. Schmid, M. Halbherr, K. Yusenko, M. Cokoja, R. A. Fischer, Angew. Chem. Int. Ed. 2009, 48, 3872-3876.[5] M. Cokoja, H. Parala, M.-K. Schröter, A. Birkner, M. W. E. van den Berg, W. Grünert, R. A. Fischer, Chem. Mater. 2006, 18, 1634-1642.[6] K. Schutte, A. Doddi, C. Kroll, H. Meyer, C. Wiktor, C. Gemel, G. van Tendeloo, R. A. Fischer, C. Janiak, Nanoscale 2014, 6, 5532-5544.

48

Takaaki Ikuno1, Maricruz Sanchez- Sanchez1, Johannes A. Lercher1

Takaaki Ikuno

Selective oxidation of methane into methanol on Cu-oxo clusters supported on microporous materials

Methane is the main component of the natural gas, which is in great abundancy and dispersed globally. However, transportation infrastructure or facile method to convert it into easily condensable energy carriers at or near the site is lacking, leading to flaring of large quantities of natural gas causing both environmental damage and economical loss. Direct oxidation of methane to methanol would help addressing this problem, but it still remains a great challenge due to higher reactivity of methanol compared to meth-ane. Cu zeolites have been found to be reactive to this reaction [1], which involves three consecutive steps: catalyst activation at high temperature (typically 450-500 °C), methane loading, and subsequent methanol desorption by steam treatment. In order to further address the partial oxidation of methane into methanol, in this study, metal-organic framework (MOF) supported Cu-based catalyst is investigated and compared to the reported Cu-ex-changed zeolite with MOR structure (Cu-MOR) [1].

NU1000 (Zr6(μ3-OH)8(OH)8(1,3,6,8-tetrakis(p-benzoate)pyrene)2) [2], possessing well-defined Zr-based nodes for the deposition of Cu-species and also significantly larger pores (~3 nm) compared to zeolites, is used as catalyst support, and Cu-species is de-posited on NU1000 by atomic layer deposition. Even though Cu-MOR is found to be more active and selective than Cu-NU1000, the latter successfully activates methane after significantly low activation temperature of 150 °C, demonstrating the application of MOF as catalysts for direct oxidation of methane into methanol at low temperatures.

[1] Grundner, S.; Markovits, M. A. C.; Li, G.; Tromp, M.; Pidko, E. A.; Hensen, E. J. M.; Jentys, A.; Sanchez-Sanchez, M.; Lercher, J. A., Nat. Commun. 2015, 6, 7546-7554.[2] Mondloch, J. E.; Bury, W.; Fairen-Jimenez, D.; Kwon, S.; DeMarco, E. J.; Weston, M. H.; Sarjeant, A. A.; Nguyen, S. T.; Stair, P. C.; Snurr, R. Q.; Farha, O. K.; Hupp, J. T., J. Am. Chem. Soc. 2013, 135, 10294-10297.

Poster


[email protected]

49

Poster

Dennis Knogler1,2, Theresa Zach1, Maximilian Krause1, Friedrich Esch1



[email protected]

Dennis Knogler

Improvement of a LEGO atomic force microscope for educational purposes with a position sensitive detector

Atomic force microscopy is a useful technique to investigate and depict the topology of surfaces in nearly atomic resolution. Due to its simplicity and its manifoldness it is widely used in a variety of facilities, ranging from small laboratories up to factories of the semiconductor industry. In order to exhibit this technique to a broad audience, an atomic force microscope built of LEGOs NXT robotic parts was assembled previously [1].

The construction as well as the LabView program for control-ling are based up on the works of the micro/nanoscale energy transport and conversion laboratory of the University of Utah. In order to resemble a real atomic force microscope even more, a position sensitive detector has been implemented. The integra-tion was possible by minor mechanical changes and usage of LabViews NXT light sensor subVIs. In contrast to the previous employed LEGO NXT light diodes a tremendous improvement in height resolution could be achieved, due to the more detailed and continuous acquirement of topographic differences. Insights in the operation and the implementation of a position sensitive detector have been gained. This will strongly promote the usage of this detector. Furthermore an impression on postprocessing the obtained data by MatLab will be presented.

[1] Albersberger S. and Braun T., LEGO AFM, TUM course ’Messen-Auswerten-und-Simulieren’ (2015)

50

Sebastian L. Kollmannsberger1, Constantin A. Walenta1, Andrea Winnerl2, Saskia Weiszer2, Rui Pereira2, Martin Tschurl1, Martin Stutzmann2, Ueli Heiz1

Sebastian Kollmannsberger

Probing semiconductor properties of GaN: Effects of doping and photon-stimulated processes

Understanding the effects of doping on semiconductors in photo-catalysis is of major importance for metal-cluster semiconductor hybrid materials [1]. One of the most stable systems is gallium nitride decorated with metal nanoparticles as a co-catalyst [2]. GaN is a semiconductor (3.4 eV band gap), which can be p- and n-doped and its band gap can be tuned by alloying.

In this work we demonstrate the elucidation of reaction pathways on clean extended GaN surfaces in the UHV with a chemical probe molecule. For this purpose CO is the molecule of choice, as it exhibits photon-stimulated desorption (PSD) upon UV irradiation on the bare semiconductor surfaces. Further, it is shown, that the CO adsorption properties are dependent on semiconductor doping, while the PSD kinetics remain the same.

A thorough characterization of the surface is of paramount im-portance and prerequisite for studies with size-selected Pt metal clusters, as we show that major change in reactivity of the clusters with different electronic properties of this hybrid materials can be expected [1, 3].

[1] Kim et al., Nano Lett., 2013, 13, 1352-1358.[2] Ohno et al., J. Am. Chem. Soc., 2012, 134, 8254-8259.[3] Winnerl et al., J. Appl. Phys., 2015, 118, 15.

Poster


2Technical University of Munich, Chair of Experimental Semiconductor Physics, Physics Department, Walter Schottky Institute and Catalysis Research Center, Am Coulombwall 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

51

Poster

Maximilian Krause1, Gregor Zwasch-ka1, Manuel Rondelli1, Dalaver Anjum2, Mohammed Nejib Hedhili2, Manuel Högerl3, Marian Rötzer1, Andrew Crampton1, Jean-Marie Basset3, Valerio D’Elia3, Florian F. Schweinberger1, Ueli Heiz1


2King Abdullah University of Science and Technology, Advanced Nanofab. Imaging and Characterization Core Lab, Bldg. 3, Thuwal 23955-6900, Kingdom of Saudi Arabia.

3King Abdullah University of Science and Technology, Kaust Catalysis Center (KCC), Bldg. 3, Thuwal 23955-6900, Kingdom of Saudi Arabia.

[email protected]

Maximilian Krause

Supported size-selected metal clusters as model systems for wet chemical applications

Precisely controlled catalytic model systems are needed for understanding fundamental aspects of heterogeneous catalysis. In this respect, supported size-selected clusters on metal oxides are an ideal choice, since their number of atoms can be tuned precisely independent of the coverage. Though considerable in-sights could be gained with such systems in the UHV [1-3] in the last decades, they can be hardly compared to applied catalytic systems, because of the well-known problematic of the pressure and complexity gaps [4].

To this end, we report results of cluster catalysis under classical wet chemistry conditions. Clusters of different metals, sizes and size-distributions, in particular Ta (1, 4, >1, >3, >11) and Pt (1, >1, >35) were deposited onto Si-wafers under vacuum and trans-ferred to ambient conditions. The catalysts were used for different test reactions: the oxidation of cyclooctene (Ta, Schlenk-Tube, 60°C) and the reduction of p-Chloronitrobenzene (Pt, autoclave, 100°C, 5 bar H2). Reaction products were quantified by GC-MS and LC measurements. Furthermore characterization by means of XPS and HAADF-STEM before and after the reactions were performed. Both metals showed promising results concerning re-activity, though their stability is limited; both parameters depend on catalyst size and material. The results demonstrate the potential of using cluster model catalyst materials for applied reaction con-ditions. It contributes towards the understanding of cluster stability in solution and reactivity of catalyst in the size regime of supported sub-nm clusters at more relevant catalytic conditions in general.

[1] Sanchez, A.; Abbet, S.; Heiz, U.; Schneider, W. D.; Häkkinen, H.; Barnett, R. N.; Landman, U. The Journal of Physical Chemistry A 1999, 103 (48), 9573.[2] Heiz, U.; Sanchez, A.; Abbet, S.; Schneider, W. D. Journal of the American Chemical Society 1999, 121 (13), 3214.[3] Abbet, S.; Sanchez, A.; Heiz, U.; Schneider, W. D.; Ferrari, A. M.; Pacchioni, G.; Rösch, N. Journal of the American Chemical Society 2000, 122 (14), 3453-3457.[4] Freund, H.-J.; Kuhlenbeck, H.; Libuda, J.; Rupprechter, G.; Bäumer, M.; Hamann, H. Topics in Catalysis 2001, 15 (2), 201.

52

Paul Leidinger1, Magdalene Böbel1, Gregor Zwaschka1, Jürgen Kraus1, Sebastian Günther1

Paul Leidinger

Supressing nucleation for chemical vapour deposition (CVD) growth of graphene

Controlling the nucleation density of graphene grown by chemical vapour deposition (CVD) on polycrystalline copper is the key for the production of large, high quality graphene single crystals. We present systematic studies that show a correlation between the carbon content of the copper foils and the graphene nucleation rate during CVD growth. The carbon content on the sample sur-face was determined by ex-situ x-ray photoelectron spectroscopy (XPS) applying a special fast cooling procedure.

Particular attention was paid on the pretreatment of the copper foils that removes carbon contaminations already present before growing graphene. One established pretreatment method of the foil is at 950°C in a highly diluted oxygen atmosphere, which oxidatively removes the carbon. Samples with minimum carbon content show a nucleation density reduced by three orders of magnitude, resulting in approximately one graphene flake per mm2. Thus, graphene flakes with diameters of up to 1 mm can be obtained in the subsequent CVD growth step.

Poster

1 Technical University of Munich, Catalysis Research Center and Chemistry Department, Associate Professorship of Physical Chemistry with Focus on Catalysis, Lichten-bergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

53

Poster

T. Lelaidier1,2, T. Lünskens2, A. von Weber2, T. Leoni1, A. Ranguis1, A. D‘Aléo1, F. Fages1, A. Kartouzian2, C. Becker1, U. Heiz2

1Centre Interdisciplinaire de Nanoscience de Marseille. UMR 7325 Aix-Marseille Université

2Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Physical Chemistry, Lichtenbergstraße 4 and Ernst-Otto-Fischer-Str. 1. 85748 Garching, Germany

3munich marseille graduate school of nanoscience (m2gsn), m2gsn.tum.de

[email protected]

Dr. Tony Lelaidier

Optical and morphological properties of thin films of bis-pyrenyl π-conjugated molecules.

The optical and morphological properties of thin film of 1,4-di-n-octyloxy-2,5-bis(pyren-1-ylethenyl)benzene (bis-pyrene) have been studied by the means of surface cavity ring-down (s-CRD) spectroscopy and scanning tunnelling microscopy under ultra high vacuum. The appearance followed by a saturation of a shoulder at 505 nm in the optical spectra has been observed as a function of the molecular density deposited on the surface.

Combining observations from these measurements of the op-tical properties obtained by s-CRDS with conventional UV-Vis measurement and STM experiment performed on Au(111) allow us to assign this modification to an interaction of the transition dipole moments of molecules of the first and the second layer. Furthermore, these experiments also reveal that the molecular growth process on the BK7 glass substrate is a Volmer-Weber growth mode, which is different from the growth mode observed for bis-pyrene on Au(111). We also observe that the substrate temperature has a strong influence on the molecular diffusion and the formation of molecular structure: higher temperature enhances the molecular diffusion, leading to the formation of multi-layers islands at lower molecular density compared to the deposition performed at lower temperature.

54

Li Jiang1, Anthoula C. Papageorgiou1, Seung Cheol Oh1, Özge Sağlam1, Joachim Reichert1, David A. Duncan1, Yi-Qi Zhang1, Florian Klappenberger1, Yuanyuan Guo1, Francesco Allegret-ti1, Sandeep More2, Rajesh Bhosale2, Aurelio Mateo-Alonso2,3, Johannes V. Barth1

Li Jiang

Toward on-surface synthesis of low dimensional conjugated nanomaterials

Recently, graphene nanoribbons, especially doped with hete-roatoms have spurred extensive attention and exploration [1] and covalent organic frameworks (COF) have been successfully syn-thesized based on Schiff base formation [2].

Inspired by these findings, we systematically investigated the coupling reaction of a tetraamine molecule with a tetraketone molecule on the three coinage close packed metal surfaces Au, Ag and Cu under ultrahigh vacuum conditions by scanning tun-neling microscopy. On all three substrates the reactants readily intermix at room temperature forming two-dimensional bi-com-ponent networks. We demonstrated the feasibility to form Schiff base conjugated oligomers on the Ag(111) surface by thermal treatment. Statistical analysis of the reaction products as a func-tion of reactant stoichiometry and further investigations with the X-ray photoelectron spectroscopy provide mechanistic insight in the on-surface polymerization process. In contrast to the behavior on Ag(111), the monomers desorb from the Au(111) surface before they react, whereas on the Cu(111) surface undesired thermal decomposition is observed after annealing at lower temperatures than that of imine formation.

[1] L. Zhao, R. He, K.T. Rim, T. Schiros, K.S. Kim, H. Zhou, C. Gutierrez, S.P. Chockalingam, C.J. Arguello, L. Palova, D. Nordlund, M.S. Hybertsen, D.R. Reichman, T.F. Heinz, P. Kim, A. Pinczuk, G.W. Flynn, and A.N. Pasupathy, Science, 2011, 333, 999.[2] L. Stegbauer, K. Schwinghammer, and B.V. Lotsch, Chem. Sci. 2014, 5, 2789.

Poster


2Universität Freiburg, Institut für Organische Chemie und Biochemie, Albertstraße 21, 79104 Freiburg, Germany

3Ikerbasque, Basque Foundation for Science E-48011 Bilbao, Spain

[email protected]

55

Poster

Pankaj Madkikar1, Thomas Mit-termeier1, Michele Piana1, Hubert Gasteiger1

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Technical Electrochemistry, Lichten-bergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Pankaj Madkikar

ZrO2/C as noble metal-free oxygen reduction reaction catalyst in PEMFC

High cost and limited availability of platinum based catalysts for Oxygen Reduction Reaction (ORR) is a major hurdle towards the commercialization of Proton Exchange Membrane Fuel Cell (PEM-FC) systems. Until today, replacing Pt by Pt-free and finally by noble-metal-free catalysts for ORR is still restricted to the labs. High activity and durability are the main requirements for a new catalyst. MNxCy system (M = Fe, Co) are favored due to their low cost, reasonable activity and remarkable selectivity towards ORR [1]. On the other hand, MNxCy catalysts have a disadvantage in their poor stability in corrosive environment. Since more than a decade, Ota et al. are studying valve metal oxides (from group IV and V) [2], observing some ORR activity for those compounds. In addition these metal oxides are stable in an acid solution.

Based on their work, we started our research on the same systems, starting with carbon supported zirconia (ZrO2) nanoparticles [3]. The samples were synthesized using two different organometallic precursors, namely, zirconium oxy-phthalocyanine (ZrOPc) and zirconium acetylacetonate (Zr(acac)4). The difference in atomic constitution and solubility in dispersing medium of the two precur-sors made their use and the investigation of the obtained catalyst interesting. From the X ray diffractograms of supported zirconia nanoparticles from both the precursors, samples synthesized from ZrOPc at ≥900 °C and from Zr(acac)4 at ≥750 °C a ZrO2 phase is assignable. The ORR electrochemical activity of these samples was tested by thin-film RDE technique at 20 °C in 0.1 M HClO4

electrolyte [4].

[1] J.-P. Dodelet in N4-Macrocyclic Metal Complexes (Eds.: J. Zagal, F. Bedioui, J.-P. Dodelet), Springer New York, 2006. [2] K.-I. Ota, A. Ishihara in Electrocatalysis in Fuel Cells (Ed.: M. Shao), Springer London, 2013.[3] S. Yin et al. ECS Transactions 2013, 50, 1785–1790. [4] U. Paulus et al. J. Electroanalytical Chemistry 2001, 495, 134.

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Iman Marhaba1, Carine Lafon1, Philippe Parent1, Daniel Ferry1, Tom Z. Rergier2

Iman Marhaba

Structure and chemistry of aircraft soot nanoparticles

Air traffic has increased of about 5%/year in the last decades but little is known about the aviation’s impact on the atmosphere [1]. Particulate emissions from jet aircrafts are the most significant source of carbonaceous particles in the upper troposphere/lower stratosphere; they also contribute to black carbon pollution in near airport areas. In the troposphere, they affect the climate system through various physical processes like scattering and absorption of solar radiation, thermal emission, and cloud formation (through ice nucleation) that modifies the Earth’s albedo. Determining their physical structure, chemistry and optical properties is then of importance to improve our knowledge about their reactivity and impact on human health and climate.

In this context, the “MERMOSE” project aims at determining physical and chemical characteristics of soot particles emitted from a modern turbofan engine (SaM146 1S17) fuelled with Jet-A1. Particles have been collected behind the engine during a sampling campaign carried out on a test bench facility. We present results obtained by HRTEM, X-Ray Photoelectron Spectroscopy (XPS) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) on the collected carbonaceous particles. The structure and elemental chemical composition as well as the chemical speciation of carbon and oxygen are presented for different thrust regimes (take-off, climb out, cruise, and final approach) [2]. We show for the first time structural and chemical differences between the outermost part and the inner part of nanometric soot primary particles.

We propose a detailed atomic representation of aircraft emitted soot particles, a key step for understanding their physical and chemical properties.

[1] M. Masiol, and R.M. Harrison, (2014) Atmos. Environ. 95, 409-455.[2] Ph. Parent, C. Laffon, I. Marhaba, D.Ferry, T.Z.Regier, I.K. Ortega, B. Chazallon, Y. Carpentier, and C. Focsa, (2016) Carbon 101, 86-100.

Poster

1Aix-Marseille Université, CINaM, campus de Luminy case 913, F-13009 Marseille - France

2Canadian Light Source, Saskatoon, SK, S7N 2V3, Canada

[email protected]

57

Poster

Amina Merabet1, Michaël Texier1, Christophe Tromas2, Anne Talneau3, Olivier Olivier1, Julien Godet1

1Aix-Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, F-13397 Marseille, France

2Institut Pprime, UPR3346 CNRS – Université de Poitiers, F-86962 Futurscope – Chasseneuil du Poitou Cedex, France

3Laboratoire de Photonique et de Nanostructures, CNRS, F-91460 Marcoussis, France

[email protected]

Amina Merabet

Plastic deformation of silicon nanostructures at room temperature: an electron microscopy investigation

The mechanical behavior of micro- and nano-structures depend on their size. While a very large number of research groups are focusing on the plastic properties of metal nano-structures, much less work has been devoted to semiconductor nano-objects. Sili-con is a very important material in modern technology and its mechanical behavior certainly deserves attention. In the bulk, Si is brittle at room temperature and needs temperatures in excess of 600°C to show ductility. Surprisingly, when the sample size decreases below few hundreds of nanometers, Si pillars may show an unexpected ductile behavior at room temperature [1] which is still not really understood. In this context, this research project aims at investigating in more details the deformation behavior of silicon nanopillars by combining experimental techniques (SEM, FIB, HRTEM) and molecular dynamics simulations. In this work various nanopillars, with different orientations and diameters, were patterned by Reactive-Ion Etching and FIB micromachining. These pillars were then compressed with a slow-strain-rate (10–4 s–1) at room temperature using a nanoindenter equipped with a flat punch and operated in displacement-control mode. Post mortem ob-servations of deformed nanopillars performed by SEM and TEM reveal the activation of different slip systems. The comparison be-tween experimental and simulated HRTEM images notably eviden-ces the simultaneous propagation of partial and perfect disloca-tions in {111} planes. In addition, unexpected plastic events have also been observed in {113} planes. Various possible deformation mechanisms involved during the nano-compression of the pillars will be described, based on the microscopic observations.

This work is performed within the framework of the ANR-funded research project «BrIttle-to-Ductile Transition in Silicon at Low di-mensions» (ANR-12-BS04-0003-01, SIMI4 program).

[1] F. Östlund et al., Brittle-to-Ductile Transition in Uniaxial Compression of Silicon Pillars at Room Temperature, Adv. Func. Mat., 19, p1(2009).

58

Vincent Mesquita1

Vincent Mesquita

Catalysis spatially resolved on a surface

The main objective of this study is to show how the probe of an atomic force microscopy (AFM) can locally and selectively initiate a chemical reaction on a surface. Scanning probe lithography (SPL) is a highly promising tool for the creation of specific nanosized patterns on a surface with high spatial resolution [1]. We have recently reported a novel approach to chemically selective lithog-raphy using an AFM probe with immobilized manganese complex homogeneous catalyst, potentially opening access to a diversity of nanoscale transformations of the surface-bound functional groups [2]. This new concept was proven for local epoxidation of alkene-terminated self-assembled monolayer (SAM) on silicon using H2O2 as an oxidant and a catalytic silicon AFM tip charged with manganese complexes with 1,3,7-triaza-cyclononane type ligand in double heterogeneous conditions. The reaction was revealed by selective grafting of N-octylpiperazine molecules or other compounds like ferrocene, fullerene or porphyrin derivatives onto the modified areas of the surface.

We have further studied the influence of the physicochemical par-ameters on the reaction yield of this chemical model reaction, like the applied force, the reaction time or the catalyst configuration. We could achieve a resolution limit of ~30nm. We found that the catalytic system is very robust and could successfully be used for grafting laterally an equivalent surface of at least 450μm2, but also vertically for sequential grafting of a 3D pyramidal edifice of up to three molecular layers high.

[1] S.A.M.Carnally, L. S. Wong, Nanoscale, 6, 4998 (2014)[2] D.A. Valyaev, et al., Chem. Sci. 4, 2815 (2013)

Poster

1Aix-Marseille Université, CNRS, IM2NP UMR 7334

[email protected]

59

Poster

Elmar Mitterreiter1,2, Marian D. Rötzer1, Florian F. Schweinberger1, Ueli Heiz1

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Physical Chemistry, Lichtenbergstraße 4 and Ernst-Otto-Fischer-Str. 1. 85748 Garching, Germany


[email protected]

Elmar Mitterreiter

Photoelectron spectroscopy study of 3-hexyne on surfaces

Current research has lead to a profound understanding of inter-action processes during the adsorption of simple molecules on surfaces. However, with respect to more complex molecule struc-tures there are still some scientifically challenges [1].

Thus, the presented study examined the adsorption properties of 3-hexyne on Pt(111) under UHV conditions using different spectro-scopic techniques such as Ultraviolet Photoelectron Spectroscopy (UPS), Metastable Impact Electron Spectroscopy (MIES) and Aug-er Electron Spectroscopy (AES) in combination with Temperature Programmed Desorption (TPD) [4]. These techniques, which are extremely surface sensitive, allow to investigate precisely the elec-tronic properties of the adsorbed molecules [2-3].

With increasing concentration of 3-hexyne on the Pt(111) surface an increasing shift of the peaks towards higher binding energies was observed up to a saturation concentration for all molecular or-bitals (MOs). Also, the value of the work function changed towards larger values as a function of coverage. The relative peak positions of the different MOs however remained unchanged. Comparing the experimental results with DFT calculations of the molecular structure of 3-hexyne, the interacting MOs were identified. Com-plementary TPD data showed for higher coverages an increased amount of 3-hexyne and also additional reaction products, such as hydrogen, hexane and benzene. These findings are interpreted in the framework of a chemisorption process [2] of 3-hexyne on the Pt(111) surface attended by self-hydrogenation/dehydrocyclization reaction pathways. Additional experiments are proposed in order to develop a better understanding of the reaction mechanism and to allow for a refined interpretation of the data.

[1] Schüth, F. Chemie in unserer Zeit, 2006, 40, 92-103.[2] Schweinberger, F.F. Catalysis with Supported Size-selected Pt Clusters, 2014, Springer Internat. Publishing.[3] Kuno, M. Introductory Nanoscience, 2011.[4] Heinz,B., Morgner, H. Journal of Electron Spectroscopy and Related Phenomena, 1998.

60

Daniel Rutz1,2, David Mayer1, Sarah Wieghold1, Friedrich Esch1, Ueli Heiz1

Daniel Rutz

Insight into electrochemical measurements of platinum nanoparticles

The future of electromobility depends on the development of bat-teries and hydrogen fuel cells, based on hydrogen produced by renewable energies [1]. It seems that this is the only opportunity to meet the European future CO2-emission targets of <95 g CO2

per km [2]. The investigation of platinum nanoparticles as potential catalysts is fundamental to fully understand the electrocatalytic hy-drogen oxidation/evolution reaction (HOR/HER) and the potential of hydrogen for energy storage in fuel cells [2, 3]. The RDE used in a three electrode system is a powerful tool when investigating reaction mechanisms related to redox reactions, such as the HER/HOR [3]. With the aid of the Levich-Equations we can predict the height of peak currents in a cyclic voltammogram (CV). The catalytic electrode surface (and consequently the roughness fac-tor) is found by integrating the reduction current in the hydrogen adsorption area. Hence, we can determine the specific catalytic activity of the nanoparticles.

We present an experimental setup, consisting of a classical three electrode system, using glassy carbon as a support material for nanoparticles (0.24 mmol Pt) in 0.1 M HClO4 (>99.99%) as electro-lyte. Moreover, a gas switch enables the usage of various gases, such like H2, Ar, O2, CO, independently. The cell is controlled by a software. Our results showed a Gaussian-like decrement of the roughness factor with increasing number of runs. This could be explained by a surface degradation of the nanoparticles [4].

[1] Gröger, O.; Gasteiger, H . A.; J. Electrochem. Soc., 2015, 162, A2605-A2622.[2] Durst, J.; Siebel, A.; Gasteiger, H., Energy and Environ. Science, 2014, 7, 2255 -2260.[3] K.J.J. Mayrhofer, M. Arenz, V. Stamenkovic, P. Ross, N. Markovic, Electrochimica Acta, 50, 2005, 5144-5154.[4] J. Meier, C. Galeano, A. Topalov, C. Baldizzone, F. Schüth, K.J.J. Mayrhofer; Beilstein J. Nanotech. 2014, 5, 44–67.

Poster



[email protected]

61

Poster

Christian Schüler1, Kai-Olaf Hinrichsen1


[email protected]

Christian Schüler

Preparation of bimetallic nickel catalysts for CO2 methanation via chemical vapor deposition

As part of the energy transition, the expansion of renewable energy is focused on reducing CO2 emissions. Here, however, it is challenging to store the excess energy effectively. A promising approach to solve this problem is the power-to-gas concept [1]. In this case, hydrogen obtained by electrolysis is converted with carbon dioxide into methane by means of the Sabatier process. From literature is known that Rh-, Ru- or Ni-based catalysts show promising catalytic results [2-4]. In this study, the performance of CVD-prepared Ni/SiO2 should be enhanced via the addition of further metals during the deposition process.

The advantage of CVD-prepared catalysts is that these catalysts have high active metal surfaces and high dispersions at low nickel loadings. The bimetallic deposition is investigated with focus on its influence on dispersion and active metal surface by means of N2 Physisorption (BET) and H2/CO2 chemisorption techniques. The received data are compared with the pure nickel catalyst to see the influence of the several doping metals. The effects on the reaction of the doping metals are evaluated by means of kinetic studies. These studies are performed in a single-pass tubular reactor where the methanation performance is determined by measuring the CO2 conversion at different temperatures. After reduction and formation of the catalyst, the kinetic performance of the catalyst is recorded and the temperature-dependent performance is compared at a conversion of 50%. The next step of this study is to combine the most promising doping metals on the nickel catalyst and investi-gate the combined effects.

[1] M. Sterner, PhD Thesis, Kassel University, 2009.[2] M. Bowker, T.J. Cassidy, A.T. Ashcroft, A.K. Cheetham, J. Catal. 143 (1993) 308–313.[3] J.M. Rynkowski, T. Paryjczak, A. Lewicki, M. Szynkowska, T.P. Maniecki, W.K. Jozwiak, React. Kinet. & Catal. Lett. 71 (2000) 55–64.[4] G.M. Shashidhara, M. Ravindram, React. Kinet. & Catal. Lett. 37 (1988) 451–456.

62

Jan N. Schwämmlein1, Hany A. El-Sayed1, Björn M. Stühmeier1, Hubert A. Gasteiger1

Jan Schwämmlein

Origin of the superior activity of bimetallic Pt-Ru catalysts towards hydrogen oxidation in alkaline media

Platinum shows an exceptionally high activity for the hydrogen oxidation reaction (HOR) in acidic environment, enabling ultra-low Pt-loadings on the anode side of proton exchange membrane fuel cells (PEMFCs) [1]. Unlike in acid, this reaction is about two orders of magnitude slower on platinum and other platinum metals in al-kaline electrolyte [2]. Bimetallic Pt-Ru catalysts were demonstrated to exhibit significantly higher HOR activities in acid [3] and base [4] compared to Pt catalysts.

One hypothesis for the high HOR activity of Pt-Ru alloys in base is a bi-functional mechanism, with hydrogen being adsorbed on Pt and hydroxide being supplied by more oxophilic Ru, whereby the presence of hydroxide in the vicinity of Pt-Hads would accel-erate the rate of the hydrogen oxidation. The second hypothesis considers a modification of the electronic structure of platinum by ruthenium [4], leading to a lower Pt Hads binding energy and ultimately to a higher activity of platinum towards the oxidation of hydrogen. While the exposure of ruthenium on the surface of the catalyst is absolutely mandatory for a bi-functional mechan-ism [5], this is not the case for an activity enhancement due to a modification of the electronic structure of platinum. Based on this fundamental difference, we have attempted to identify the actual HOR mechanism on bimetallic Pt-Ru catalysts by evaluating Ru@Pt core-shell nanoparticles with various Pt-coverages and shell thicknesses.

[1] H. A. Gasteiger; J. E. Panels and S. G. Yan, J. Power Sources, 1-2, 162 (2004).[2] P. J. Rheinländer; J. Herranz; J. Durst and H. A. Gasteiger, J. Electrochem. Soc., 14, F1448–F1457 (2014).[3] J. X. Wang; Y. Zhang; C. B. Capuano and K. E. Ayers, Scientific reports, 12220 (2015).[4] K. Elbert; J. Hu; Z. Ma; Y. Zhang; G. Chen; W. An; P. Liu; H. S. Isaacs; R. R. Adzic and J. X. Wang, ACS Catal., 11, 6764 (2015).[5] S. St. John; R. W. Atkinson; R. R. Unocic; T. A. Zawodzinski A. B. Papandrew, J. Phys. Chem. C, 24, 13481 (2015).

Poster

1Technical University of Munich, Catalysis Research Center and Chemistry Department, Chair of Technical Electrochemistry, Lichten-bergstraße 4 and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

63

Poster

Sumanth Ranganathan1, Paul Stock-mann1, Volker Sieber1

1Technical University of Munich, Catalysis Research Center and Straubing Center of Science, Chair of Chemistry of Biogenic Resources, Schulgasse 1, 94315 Straubing and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Paul Stockmann

Development of an enzyme mediated terpene epoxidation process

The epoxidation of terpenes is of great interest owing to the fact that they are valuable chemicals in the fragrance, cosmetic and in the near future polymer industries. The epoxides are intermediates to the upcoming steps in the polymer synthesis. An enzymatic epoxidation procedure was optimized using the Taguchi method of parameter optimization and is presented here. Mild reaction con-ditions, easy work-up make this process a simple and an easy to scale-up one. The monoterpenes limonene, 3-carene and α-pinene have been epoxidized and obtained with an isolated yield of 62.5, 88.8 and 72.3%. Moreover, the selective epoxidation of limonene (a diene) was also developed which could be further extended to all dienes in the future. The first step of the polymerization procedure was the rearrangement to a ketone which was done chemically using Lewis acids.

With this new approach of olefin to ketone, the way toward green monomers for polymerization could be achieved with relative ease.

64

Moritz Wolf1, Elena Fritzler1, Yang Wang1, Kai-Olaf Hinrichsen1

Moritz Wolf

CO2 methanation: deactivation due to sulfur poisoning

Catalyst deactivation due to sulfur poisoning is a common problem for a wide range of catalytic processes. In the current study, the poisoning effect of sulfur on the methanation of CO2 over different nickel and sulfur loadings was studied. Therefore, catalysts were poisoned using the ex-situ method [1]. The activity of the as-pre-pared catalysts was tested in a plug flow reactor, characterization was done via elemental analysis, XRD and XPS.

Supported nickel catalysts were prepared by incipient-wetness impregnation or co-precipitation, dried and calcined. These refer-ence samples were poisoned in a subsequent step via the ex-situ method, using an aqueous solution of ammonium sulfate [1]. The reference and poisoned samples were tested for activity in a single pass plug flow reactor. Hereby, the performed activity measure-ments all followed the same routine procedure.

Characterization of the bulk material by XRD analysis confirmed, that the bulk morphology of the catalysts was not significantly affected upon the addition of small amounts of sulfur. In contrast to that, a sulfate signal in the S 2p spectral region was observed during XPS analysis [2]. The catalytic tests showed, that sulfur addition has a significant effect on the CO2 methanation reaction. A dramatic loss of activity was observed.

On the basis of this study, we are able to compare the perform-ance of different catalytic systems in the presence of sulfur and to develop different approaches to increase sulfur tolerance.

[1] V. Curtis, C. P. Nicolaides, N. J. Coville, D. Hildebrandt, D. Glasser, Catal. Today 49 (1999) 33-40.[2] J. F. Moulder, W. F. Stickle, P. E. Sobol, K. D. Bomben, Phys. Electron. (1995) 60-61.

Poster


[email protected]

65

Poster

Ioannis Zachos1, Josef Sperl1, Volker Sieber1

1Technical University of Munich, Catalysis Research Center and Straubing Center of Science, Chair of Chemistry of Biogenic Resources, Schulgasse 1, 94315 Straubing and Ernst-Otto-Fischer-Str. 1, 85748 Garching, Germany

[email protected]

Ioannis Zachos

Photocatalytic activated reduction module for enzymatic processes

Photocatalytic water splitting is an artificial photosynthesis pro-cess with photocatalysis in a reaction cell used for the dissociation of water into its constituent parts, hydrogen and oxygen, using either artificial or natural light. Theoretically, only solar energy, water, and a catalyst are needed. The successfull combination of photocatalysis and biocatalysis is the aim of PHAROS (Photo-catalytic activated reduction module for enzymatic processes).

Here we want to drive enzymatic redox reactions with the power of light and thus create an efficient and green way to perform many interesting reactions.

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Dr. Allegretti Francesco [email protected]. Auwärter Willi [email protected]. Barth Johannes [email protected] Bartl Johannes [email protected]. Becker Conrad [email protected] Brenninger Christoph [email protected]. Carsten Jörg [email protected]. Chorkendorff Ib [email protected]. Costas Miquel [email protected] Courtois Carla [email protected] Diouf Maïmouna [email protected] Ducke Jacob [email protected] Epp Konstantin [email protected] Ewald Stefan [email protected]. Ferry Daniel [email protected]. Fischer Richard [email protected] Garbe Steffen [email protected]. Garcia Hermenegildo [email protected]. Giorgio Suzanne [email protected] Grötsch Irmgard [email protected]. Günther Sebastian [email protected]. Gutierrez Olivier [email protected] Haas Ruth [email protected]. Heiz Ulrich [email protected]. Hess Corinna [email protected]. Hintermann Lukas [email protected] Hofmann Benjamin [email protected] Hölzl Alena alena.hö[email protected] Hornung Julius [email protected] Ikuno Takaaki [email protected]. Inoue Shigeyoshi [email protected] Kaspar Manuel [email protected] Kirchberger Felix [email protected] Knogler Dennis [email protected]. Köhler Klaus [email protected] Kollmansberger Sebastian [email protected] Kratky Tim [email protected] Kraus Jürgen [email protected] Krause Maximilian [email protected] Leibold Joachim [email protected] Leidinger Paul [email protected]. Lelaidier Tony [email protected]. Lercher Johannes [email protected] Li Jiang [email protected] Li Han [email protected]

Participants

67

Participants

Madkikar Pankaj [email protected] Marangos Nicole-Artemis [email protected] Marhaba Iman [email protected] Merabet Amina [email protected] Mesquita Vincent [email protected]. Mihalios Dimitrios [email protected] Mitterreiter Elmar [email protected]. Niemantsverdriet Hans [email protected]. Papageorgiou Anthoula [email protected] Rötzer Marian [email protected] Rutz Daniel [email protected] Sanwald Kai [email protected] Sarkar Debotra [email protected] Schüler Christian [email protected] Schwämmlein Jan [email protected] Schwarz Martin [email protected]. Schweinberger Florian [email protected]. Sieber Volker [email protected] Standl Sebastian [email protected] Stockmann Paul [email protected]. Strassburg Martin [email protected]. Thomas Cornelius [email protected]. Thomys Oliver [email protected]. Udishnu Sanyal [email protected] Walenta Constantin [email protected] Wolf Moritz [email protected] Zachos Ioannis [email protected]

Technical University of Munich Catalysis Research Center

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