11

Nanomaterialer – viktig for gode framtidige løsninger for energi og miljø

Professor Magnus RønningInstitutt for kjemisk prosessteknologi,

Norges teknisk-naturvitenskapelige universitet, NTNUTrondheim

Nanotechnology applications NTNU

Fuelcells

Solarcells

Batteries/ energy storage

Green Energy

Hydrogen

Better air quality

Water treatment

Environment

CO2capture

Health

Diagnostics

Drug delivery

Lab-on-a-chip

Tissueon a chip

ICTData storage

Novel semiconductor

devices

Sensors

Oil production

Nanomechanics

Oil Gas Minerals

Toolboxes available at NTNUTheory/

modellingCharacterisation/

ValidationSynthesis/

Nanostructuring

New Materialsand

Technologies

NTNU NanoLab• Research

3 scientific areas:- Bionanotechnology- Nano-component technology - Nanotechnology for green energy systems

• Infrastructure NanoLab Cleanroom

- Investment 200 MNOK- Operating budget about 20 MNOK/year

Several other nano-related laboratory facilities

• EducationMSc. Study program in Nanotechnology

© 2006 Bruno & Lígia Rodrigues.

Challenge 1: Greenhouse gases - CO2 capture in power plants and process industry

Membranes for CO2 capture: in post combustion –in precombustion – in oxyfuel combustion –environmental friendly processes – no chemicals needed

New membrane materials investigated on nanoscale1. Hybrid materials / NanocompositesThe membrane can be tailored using nanoparticles to increase the separation of gas components

PMP with 25% TiO2 Self-organised PVAc with ZA4

2. Carbon Molecular Sieve MembranesPores are tailored in the range less than 1 nm– from Hollow Polymeric Fibres to CMS membranes by controlled pyrolysis

3. Facilitated Transport Membranes withNanoscale carriers in the material

Enzymes are mobile carriers (For CO2 capture we learn from nature – breathing)

The enzyme carbonic anhydrase (CA) helps to transport CO2 as HCO3

-

The NTNU Fixed Site Carrier (FSC) membrane is mimicking nature

H2O in the flue gas helpsto convert the CO2 to HCO3

- in the PVAmMembrane, hence CO2

capture is very efficient

May-Britt Hägg, NTNU

From NANO in lab to DEMO at site -minimum ~15 years – research takes time

Carbon Molecular Sieve MembranesRenewable Energy: In 2008 a NTNU spin-off company, MemfoACT, was established based on this patented technology,

• Producing membranes for upgrading of biogas to high quality fuels

• The company has now a demonstration pilot at GLØR biogas plant, Lillehammer

CO2 capture with FSC membrane Developed at NTNU – demonstrated on small pilot scale at a coal fired power plant in Portugal 2011Currently setting up a project team with international partners for scaling up the membrane towards demo

At EDP’s power plant In Sines, Portugal

May-Britt Hägg, NTNU

Challenge 2: Renewable energy:-Preparing membranes for saline power production

SEM images of membranes with the different linking monomers

Trimesoyl chlorideSuccinyl chloride Malonyl chloride

The membrane must be very thin(a few nanometres) in order to achievehigh power density

Key components: Pressure exchanger and membrane

Key components: Pressure exchanger and membrane

Global potential: 1600‐1700 TWh/annually

Global potential: 1600‐1700 TWh/annually

May-Britt Hägg, NTNU

Challenge 3: Air pollution – NOx and NH3-Commitment through the Gothenberg Protocol

Problem:

Nitrogen oxides (NOx) are still a severe environmental problem despite decades of global focus

Norwegian NOx emissions for 2011 was 14% higher than the Norwegian obligation in the Gothenberg Protocol

Main sources of NOx

• Any process involving nitrogen and oxygen at high temperature

• Combustion (also internal combustion engines)

• Nitric acid production

• Pyrometallurgy

Harmful effects of NOx

• It is a lung irritant and may aggravate lung disease

• It contributes to acid rain and photochemical smog

• It may react with organic compounds in the atmosphere to form ground-level ozone

www.klif.no:

How can we fulfil our obligations?

Solution:

It is evident that an increased effort involving novel approaches are necessary in order to achieve a technology breakthrough:

Nanoscale control of all stages in the process:

• Selective catalytic reduction (SCR)

• Wet scrubbing

• Separation and direct decomposition

Opportunities:

Local Norwegian advantage:

Yara international ASA is a world leading company in the the field of Nitrogen and NOx chemistry and the largest producer of fertilizer in the world.

A large offshore and shipping industry with an interest in meeting the increasingly strict legislations.

High-profile research groups with decades of experience in NOx chemistry and catalysis at SINTEF, UiO, TUC and NTNU

Selective catalytic reduction (SCR) is the state of the art in NOx removal from heavy engine exhaust, in which NOx is reduced by ammonia (often generated in situ from urea).

Magnus Rønning, Edd A. Blekkan, NTNU

Well-defined nanoparticles:Composition, size, stability

SCR: Ordered mesoporous alumina with controlled pore structure and acidity:

Challenge 4: Utilisation of our natural gas resources -Natural gas conversion

Opportunities:

• Large natural gas reserves:

• At present: The gas is exported as natural gas

• New scenario: Shale-gas gives low gas prices

• Solution: Upgrading and refining to value-added products:

• Synthetic fuels and chemicals (gas to liquids)• Commercial interest from Norwegian industry• Technology can also be applied to biomass (BTL)

http://www.regjeringen.no

http://www.creditwritedowns.com

Will Norway be an important supplier of oil and natural gas also in the next decades?

Natural gas valorisation: -Liquid fuels productionGas to liquids (GTL):

• A chemical process converting natural gas to hydrocarbons using Fischer-Tropsch synthesis

• Several large-scale commercial plants world-wide, such as the Shell PEARL facility in Qatar (below)

• The PEARL GTL plant produces 140,000 barrels of GTL products per day

• The Fischer-Tropsch synthesis is carried out using cobalt nanoparticles as catalyst

• The Fischer-Tropsch reactor in the PEARL plant contains 1025 cobalt nanoparticles

http://www.shell.com

13 Magnus Rønning, ICEC 2012

The Fischer-Tropsch synthesis

H C Co AlO

H2:CO:CO2

Natural Gas

Synthesis gas production

Fischer-Tropsch Synthesis

Product upgrade (Hydrogenation - Hydrocracking)

SteamOxygen

/ steam

-CH2-

15-25%

65-85%

0-30%

FT-DieselConventional

Diesel

27

Co58.93

• Reaction mechanism? • Structure sensitivity?• Active phase?• Main deactivation mechanism?

Complexity

Magnus Rønning, Anders Holmen, John Walmsley, NTNU, Statoil, SINTEF

14 Magnus Rønning, ICEC 2012

Catalyst deactivation in Fischer-Tropsch synthesis

Re-oxidation

Carbidisation

Carbon formation

Co-support mixed compounds

Attrition

Surface reconstruction

Phase transformation

Poisoning

Sintering

H O C Co Al S

Cobalt crystallites

Support

Amorphous

Sulphur

Nitrogen

Crystalline

N.E. Tsakoumis, M. Rønning, Ø. Borg, E. Rytter, A. Holmen, Deactivation of cobalt based Fischer-Tropsch catalysts: A review, Catal. Today, 154 (2010), 162-182

TOS

Catalyst activity (a.u.) Initial

deactivation

Long term deactivation

Magnus Rønning, Anders Holmen, NTNU, Statoil, SINTEF

Advanced characterisation at industrially relevant reaction conditions

The formation of divalent tetrahedrallycoordinated cobalt observed duringreaction using synchrotron radiation

N.E. Tsakoumis, A. Voronov, M. Rønning, W. van Beek, Ø. Borg, E. Rytter, A. Holmen, J. Catal. 291 (2012) 138–148

@ 18bar, 220oC, >61% CO conv. (32 h)

XAS

XRD

Raman

MS

European Synchrotron Radiation Facility (ESRF), France

Quartz capillary reactor:1 mm in ø, 20 μm wall thickness

Adsorption of CO on Co(1120) as observed by Scanning Tunnelling Microscopy (STM): Atomic resolution

Hilde Venvik, Anne Borg NTNU

Adsorption of CO on Co(11-20) as observed by Scanning Tunnelling Microscopy (STM):

• CO makes the Co atoms at the step edges mobile!

• The surface becomes reconstructed

Hilde J. Venvik, Cecilie Berg and Anne Borg: Surface Science 397 (1998) 322

3.8 nm

Clean Co(11-20) surfacewith Co atoms visible

Reconstructed Co(11-20) surface with CO adsorbed

(1x1) unit cell

Sequence of 100 nm x 100 nm STM images with increasing CO exposure @ ~2x10-9 mbar: • CO saturation, surface fully covered by

trough-and-ridge structure. • Well-ordered regions display (3 x 1) periodicity

http://www.wired.com

Challenge 5: Energy storage-Li-ion batteries

Problem:

• Current Li-based battery technology is not sufficiently stable and safe

• High-energy chemistry involved

• The short-term fix is the old Ni-Cd batteries…

• How can we improve the current technology?

Challenge 5: Energy storage-High energy and power density

Energy & Environmental Science, 2010, 3(2)

MnOx based Li-ion batteries• Environmentally friendly and safe

• Low price and abundant

• Properties:

• Capacity: 1232/308 mAh g-1

• Voltage: 0.4/3 V vs Li+/Li

Problems:

• Poor cyclic stability

• Poor rate capability

MnO6 Octahedron

Morphology and microstructures of aligned carbon nanotubes and ACNT@MnO2

ACNT MnO2_6h

Voltage profiles and stability

De Chen, Fride Vullum-Bruer, NTNU

Methanol fuel cells (alternative to battery?)• High energy density

• Easy methanol handling using already available petrol distribution network

• Pt and Pt alloy are typical anode catalysts

Drawbacks

• Expensive

• Slow anode kinetics (CO poisoning)

• Methanol cross-over

Improvement of CO tolerance eHCO Ru Pt OH-Ru CO-Pt 2

Lowering the Pt-CO bond strength or enhance the reactivity of adsorbed CO ?

The ligand effect (the electronic effect)

Challenge 6: Energy conversion-Replace the internal combustion engine by 2050?

Strategy of improving the dispersion of Ptnanoparticles on carbon nanofibres (CNF)

Catalysts preparation (Ex-situ polyol method)Deposition of pre-synthesized Pt colloids on carbon materials with different surface oxygen groups

Refluxed at 145o Cin N2 atm for 3 hr

Dark color

H2PtCl6 solution in EG + 0.5M NaOH

(pH 12)Golden Yellow color

XC72 (1.6 % O cont)

XC72_N (5.5 % O cont)

CNF_N(6 % O cont)

CNF_N_1K(1.8 % O cont)

Pt-XC72 Pt-XC72_N Pt-CNF_N Pt-CNF_N_1K

Pt0 colloidal solution

TEM images of Pt NCs in colloidal and on various

carbon supports with the Ptwt % in the range 16-18%

Colloidal solution

2.9 ± 1.5 nm 3.5 ± 1.5 nm 4.7 ± 3.5 nm 3.4 ± 1.5 nm

2.4 ± 1.0 nm

Svein Sunde, De Chen, Magnus Rønning, NTNU

Electrochemical oxidation of methanol on Pt/C Three key parameters:

1) Pt particle size

2) Support material

3) Surface oxygen groups

• Oxygen deficit surfaces provide better Pt dispersion

• Site activity is higher on the oxygen deficient catalysts than the oxygen rich catalyst

• More active than the commercial catalyst (E-TEK)

(a) (b)

Svein Sunde, De Chen, Magnus Rønning, NTNU

Challenge 7: Noble metals as long-term solution?-Dependency on scarce and expensive materials

Johnson-Matthey Platinum interim report 2012

Teknisk Ukeblad 2012

Doped carbon nanostructures as metal-free catalysts (FREECATS)

EU-FP7 NMP project coordinated by NTNU: Professor Magnus Rønning

Development of new metal-free catalysts, either in the form of bulk nanomaterials or in hierarchically organised structures capable to replace traditional noble metal-based catalysts

The application of the new materials will eliminate the use for platinum group metals and rare earth elements such as ceria used in:• Fuel cell technology (automotive applications and others, oxygen reduction reaction) • Production of light olefins (oxidative dehydrogenation of light alkanes)• Wastewater and water purification (catalytic wet air oxidation, ozonation, photocatalysis)

http://freecats.eu

10 partners, also Prototech, Bergen

Synthesis of N/P/B-doped CNT by ex-situ organic functionalization

up to 8 mg/mLDMF, 160°C, 72h

15-30 nm

Giuliano Giambastiani (CNR, Florence), Cuong Pham-Huu, CNRS Strasbourg, Charlotte Pham, SiCAT, Germany

Ex-situ doping of carbon nanotubes with different N-species

http://freecats.eu

In-situ functionalization of N-doped CNF/Graphite

Sparger

Gas mixture:- C2H6/CO/NH3, H2 and Ar

Catalyst for CNF synthesis:- 20% Fe/Al2O3

- 10% Fe/Exfoliated Graphite

N-CNT

http://freecats.eu

Reactor

Gas feed

De Chen, Magnus Rønning, NTNU

Immobilisation of Nanoparticles:-Macroscopic N/P/B-doped catalysts on silicon carbide (SiC) foams

1 µm

CNT/SiC foam CNT/SiC foamSiC foamCarbon nanotubes supported on SiC foam composite

Hierarchical structures with high effective surface area and low diffusion path

The concentration of the doped CNT or CNF can be controlled

The pore size window can be tailored to fit the downstream applications

Courtesy of SICAT

http://freecats.eu

Summary• Nanomaterials are already playing an important role in

energy and environmental technology

• Mastering synthesis and properties at atomic level is necessary for:• Bringing existing processes to a new level• Introducing new technologies

• Highly competitive discipline• National priorities required

• Need for short-term and long-term solutions • Parallel development