Supporting Information for

A Versatile Method for the Preparation of Carbon-Rhodium Hybrid Catalysts on Graphene and Carbon Black

Chin Min Wong[a,b], D. Barney Walker[a,b], Alexander H. Soeriyadi[a], J. Justin Gooding[a] and Barbara A. Messerle*[a,b]

[a] C. M. Wong, Dr. D. B. Walker, Dr. A. H. Soeriyadi, Prof. J. J. Gooding, Prof. B. A. MesserleDepartment of ChemistryUniversity of New South Wales Sydney NSW 2052, AustraliaE-mail: barbara.messerle@mq.edu.au

[b] C. M. Wong, Dr. D. B. Walker, Prof. B. A. MesserleDepartment of Chemistry and Biomolecular SciencesMacquarie UniversitySydney NSW 2109, Australia

Electronic Supplementary Material (ESI) for Chemical Science.This journal is © The Royal Society of Chemistry 2015

2

SI Table of Contents

Entry Page

SI-1. Additional Experimental Scheme and Chemical Figures 3

SI-2. X-ray Photoelectron Spectroscopy (XPS) 5

SI-3. Thermogravimetric Analysis (TGA) 17

SI-4. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) or

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

20

SI-5. Electrochemistry 21

SI-6. Infrared Spectroscopy 23

SI-7. Raman Spectroscopy 25

SI-8. Scanning Electron Microscopy (SEM) 27

SI-9. Transmission Electron Microscopy (TEM) 29

SI-10. Catalysis and Recycling Experiment 31

SI-11. References 35

3

SI-1: Additional Experimental Scheme and Chemical Figures

NN

NN

N

Mes

H2N1

Br

NN

NN

N

Mes

O2N

Br

NN Mes Br N3

NO2

CuSO4.5H2O (5 mol%)NaAscorbate (20 mol%)

iPrOH:H2O (2:1)

NH2NH2.H2OPd/C

methanol

Scheme S1. Synthesis of ligand 1.

Table S1. Figures and atom numbering corresponding to experimental characterization.

Entry Figure Name Figure and Numbering

1

1-mesityl-3-((1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)methyl)-1H-imidazol-3-ium bromide, [MesCaTPh-NO2] - nitro functionalized ligand precursor to ligand 1

NN

NN

N

Mes

O2N

Br

2

45

5'

om

2

3-((1-(4-aminophenyl)-1H-1,2,3-triazol-4-yl)methyl)-1-mesityl-1H-imidazol-3-ium bromide, (1)

NN

NN

N

Mes

H2N

Br

2

45

5'

om

1

4

3 [1Rh(COD)]BPh4

NN

NN

NRh

Mes

H2N

BPh4

[1Rh(COD)]BPh4

45

5'

om

4 [2Rh(COD)]BPh4

NN

NN

NRh

Mes BPh4

[2Rh(COD)]BPh4

45

5'

om

p

5 [2Rh(CO)2]BPh4

NN

NN

NRh

CO

CO

Mes BPh4

[2Rh(CO)2]BPh4

45

5'

om

p

5

SI-2. X-ray Photoelectron spectrometer (XPS). Surface analysis of modified surfaces was performed by XPS using an EscaLab 250 Xi (Thermo Scientific) spectrometer with a monochromated Al Kα source. The measurements were recorded at a pressure of below 10−8 mbar in the analysis chamber and a take-off angle normal to the sample surface. The pass energy and the step size for the survey scan was 100 and 1.0 eV, respectively, and 20 and 0.1 eV, respectively, when monitoring narrow scans. Spectral analysis was performed using the Avantage 4.73 software, the background spectra were considered as Shirley type and curve fitting was carried out using a mixture of Gaussian–Lorentzian functions.

Table S2. Selected binding energies in the XP spectra of [2Rh(CO)2]BPh4, [GC-2Rh(CO)2], [CB-2Rh(CO)2] and [G-2Rh(CO)2] and their respective relative abundance of N:Rh.

Binding Energy (eV)

N1sHybrid Catalyst

N1s A

N1s B

N1s C

Rh3d5/2

Atomic Ratio N:Rh

[2Rh(CO)2]BPh4 - 401.3 402.7 309.6 5.3:1

[GC-2Rh(CO)2] 399.0 400.9 402.0 310.1 4.2:1

[CB-2Rh(CO)2] 400.5 401.4 402.5 310.1 3.8:1

[G-2Rh(CO)2] 400.1 401.5 402.7 310.6 4.6:1

Calculations of N:Rh ratio

Atomic ratio of N:Rh for [G-2Rh(CO)2] = (sum of atomic percent of N1s B and N1s C): atomic percent of Rh = (2.76+1.84):1.00 = 4.6:1

Atomic ratio of N:Rh for [GC-2Rh(CO)2] = (sum of atomic percent of N1s B and N1s C): atomic percent of Rh = (1.97+4.48):1.52 = 4.2:1

Atomic ratio of N:Rh for [CB-2Rh(CO)2] = (sum of atomic percent of N1s B and N1s C): atomic percent of Rh = (2.54+1.81):1.16 = 3.8:1

Atomic ratio of N:Rh for [2Rh(CO)2]BPh4 = (sum of atomic percent of N1s B and N1s C): atomic percent of Rh = (7.24+1.14):1.58 = 5.3:1

6

1200 1000 800 600 400 200 00

50000

100000

150000

200000

250000

300000

350000

Cou

nts

Binding Energy (eV)

C1s

O1sN1s

Figure S1. Survey scan of XP spectra for unmodified glassy carbon (GC).

Table S3. Peak Table of XP spectra for unmodified glassy carbon (GC).

Name Start BE (eV)

Peak BE (eV)

End BE (eV)

Atomic %

C1s C-C 289.98 284.96 282.08 76.80C1s C-O 289.98 285.75 282.08 12.33C1s C=O 289.98 286.48 282.08 4.85

C1s O-C=O 289.98 287.23 282.08 2.27N1s A 405.78 400.15 393.68 0.70O1s A 537.68 532.46 528.18 1.81O1s B 537.68 534.13 528.18 1.23

7

1200 1000 800 600 400 200 00

100000

200000

300000

400000

500000

600000

700000

Cou

nts

Binding Energy (eV)

C1s

O1s

Figure S2. Survey scan of XP spectra for unmodified carbon black (CB).

Table S4. Peak Table of XP spectra for unmodified carbon black (CB).

NameStart BE (eV)

Peak BE (eV)

End BE (eV)

Atomic %

C1s 289.08 284.81 281.28 78.23C1s A 289.08 285.65 281.28 21.01O1s 537.08 532.78 527.78 0.77

8

1200 1000 800 600 400 200 00

50000

100000

150000

200000

250000

300000

C

ount

s

Binding Energy (eV)

C1s

O1s

Figure S3. Survey scan of XP spectra for unmodified graphene (G).

Table S5. Peak Table of XP spectra for unmodified graphene (G).

Name Start BE (eV)

Peak BE (eV)

End BE (eV)

Atomic %

C1s C-C network 290.67 284.69 282.95 56.48C1s B 290.67 286.53 282.95 8.05

C1s COO 290.67 289.03 282.95 2.92C1s C-O 290.67 287.65 282.95 2.85C1s C-C

hydrocarbon 290.67 285.40 282.95 12.62

O1s A 539.98 531.98 527.88 6.55O1s B 539.98 533.53 527.88 9.77

Si2p3 A 106.38 101.74 98.98 0.37Si2p1 A 106.38 102.64 98.98 0.37

9

1200 1000 800 600 400 200 00

50000

100000

150000

200000

Cou

nts

Binding Energy (eV)

C1s

O1s

N1s

Rh3d

Rh3p

Figure S4. Survey scan of XP spectra for [GC-2Rh(CO)2].

10

600 400 2000

50000

100000

150000

200000

404 403 402 401 400 399 398 397 318 316 314 312 310 308

Cou

nts

Binding Energy (eV)

Binding Energy (eV)

Binding Energy (eV)

N1s

N1s

C1s

Rh3dO1s

Rh3p

Rh3d Rh3d5/2

Rh3d3/2

Figure S5. Narrow scan of N1s and Rh3d on survey scan of XP spectra for [GC-2Rh(CO)2].

Table S6. Peak Table of XP spectra for [GC-2Rh(CO)2].

NameStart BE (eV)

Peak BE (eV)

End BE (eV)

Atomic. %

C1s A 293.58 284.44 281.48 25.41C1s B 293.58 284.94 281.48 34.24C1s C 293.58 286.24 281.48 12.51C1s D 293.58 287.94 281.48 0.70C1s E 293.58 291.70 281.48 1.26

Cl2p3 A 203.78 200.37 194.68 2.24Cl2p3 B 203.78 197.98 194.68 3.40N1s B 404.28 400.90 395.58 4.48N1s C 404.28 401.95 395.58 1.97N1s A 404.28 398.95 395.58 1.22O1s 536.68 532.19 527.88 7.38Si2p 105.68 101.99 99.28 2.11

Rh3d5 318.65 310.10 307.01 1.52

11

AF1s A 692.68 688.40 684.18 1.55

1200 1000 800 600 400 200 00

50000

100000

150000

200000

C

ount

s

Binding Energy (eV)

C1s

O1s

N1s

Rh3d

Rh3p

Figure S6. Survey scan of XP spectra for [GC-2Rh(CO)2] after run 2 of catalysis.

Table S7. Peak Table of XP spectra for [GC-2Rh(CO)2] after run 2 of catalysis.

NameStart BE (eV)

Peak BE (eV)

End BE (eV)

Atomic. %

C1s A 291.98 284.43 281.78 57.93C1s B 291.98 285.44 281.78 14.97C1s C 291.98 286.46 281.78 8.04C1s D 291.98 287.73 281.78 2.22

Cl2p3 A 207.98 198.19 196.08 0.33Cl2p3 B 207.98 200.28 196.08 1.11N1s A 406.88 399.63 395.08 1.13N1s B 406.88 400.73 395.08 1.36N1s C 406.88 401.95 395.08 0.72O1s A 538.38 532.24 527.98 11.46Rh3d5

A 318.28 309.39 305.18 0.72

12

1200 1000 800 600 400 200 00

50000

100000

150000

200000

250000

Cou

nts

Binding Energy (eV)

C1s

O1sN1s

Rh3d

Rh3p

Figure S7. Survey scan of XP spectra for [CB-2Rh(CO)2].

600 550 500 450 400 350 300 250 2000

50000

100000

150000

200000

250000

405 404 403 402 401 400 399 318 316 314 312 310 308

Cou

nts

Binding Energy (eV)

Binding Energy (eV)

Binding Energy (eV)

N1s

N1s

C1s

Rh3dO1s Rh3p

Rh3d Rh3d5/2

Rh3d3/2

Figure S8. Narrow scan of N1s and Rh3d on survey scan of XP spectra for [CB-2Rh(CO)2].

13

Table S8. Peak Table of XP spectra for [CB-2Rh(CO)2].

NameStart BE (eV)

Peak BE (eV)

End BE (eV)

Atomic %

C1s C-C 289.48 284.84 282.88 68.21C1s C-O or

C-N 289.48 286.06 282.88 13.45

C1s C=O or C=N 289.48 287.15 282.88 5.37

Cl2p3 A 204.38 198.48 195.08 3.24N1s A 406.08 400.48 397.28 0.54N1s B 406.08 401.37 397.28 1.81N1s C 406.08 402.52 397.28 2.54O1s A 537.98 533.32 528.68 3.40

Rh3d5 Rh-CB 318.28 310.07 307.08 1.16

Rh3d5 Rh physically 318.28 308.35 307.08 0.06

S2p3 A 167.78 164.03 160.58 0.21

14

1200 1000 800 600 400 200 00

50000

100000

150000

200000

250000

Cou

nts

Binding Energy (eV)

C1s

O1sN1s

Rh3d

Rh3p

Figure S9. Survey scan of XP spectra for [G-2Rh(CO)2].

Table S9. Peak Table of XP spectra for [G-2Rh(CO)2].

NameStart BE (eV)

Peak BE (eV)

End BE (eV)

FWHM (eV)

Atomic. %

C1s A 291.88 285 281.78 1.06 71.60C1s B 291.88 286.23 281.78 1.06 11.85C1s C 291.88 287.29 281.78 1.06 4.69

Cl2p3 A 203.88 198.74 196.58 1.48 2.18N1s C 406.58 400.09 396.88 1.44 0.40N1s B 406.58 401.45 396.88 1.44 2.76N1s A 406.58 402.68 396.88 1.44 1.84O1s A 537.78 532.87 529.08 1.71 2.94O1s B 537.78 534.79 529.08 1.71 0.75Rh3d5

A 317.57 310.64 308.31 1.89 1.00

15

1200 1000 800 600 400 2000

50000

100000

150000

200000

250000

300000

Cou

nts

Binding Energy (eV)

C1s

O1s

N1s

Rh3d

Rh3p

Figure S10. Survey scan of XP spectra for unattached complex [2Rh(CO)2]BPh4.

16

600 550 500 450 400 350 300 250 2000

50000

100000

150000

200000

250000

300000

406 405 404 403 402 401 400 399 398 320 318 316 314 312 310 308 306

Cou

nts

Binding Energy (eV)

Binding Energy (eV)

Binding Energy (eV)

N1s

N1s

C1s

Rh3dO1sRh3p

Rh3dRh3d5/2

Rh3d3/2

Figure S11. Narrow scan of N1s and Rh3d on survey scan of XP spectra for

[2Rh(CO)2]BPh4.

Table S10. Peak Table of XP spectra for [2Rh(CO)2]BPh4.

NameStart BE (eV)

Peak BE (eV)

End BE (eV)

FWHM (eV)

Atomic %

C1s A 294.32 284.62 281.97 1.77 60.46C1s B 294.32 286.13 281.97 1.77 19.34C1s C 294.32 291.28 281.97 1.77 2.18N1s B 405.98 401.32 397.78 1.39 7.24N1s C 405.98 402.72 397.78 1.05 1.14O1s A 538.38 534.7 528.08 1.42 1.20O1s B 538.38 532.44 528.08 1.85 4.65B1s A 193.08 187.49 185.28 1.24 1.92B1s B 193.08 189.5 185.28 1.24 0.29Rh3d5 311.68 309.63 305.48 2.06 1.58

17

SI-3. Thermogravimetric Analysis (TGA). Thermogravimetric analysis was conducted using a Perkin Elmer Thermogravimetric Analyser Q5000 V3.15 instrument. The temperature scan was ramped from 20-100 °C with a scan rate of 20 °C min-1 and then kept at isothermal 100 °C for 10 minutes. The temperature was ramped again from 100-800 °C for carbon black samples and 100-800 °C for graphene samples with a scan rate of 10 °C min−1. The TGA analysis for all samples was analyzed in a nitrogen atmosphere with the gas flow rate of 40 mL per minute.

Table S11. Summary of amount of Rh on the carbon surfaces obtained from TGA, ICP-OES or electrochemistry.

Amount of Rh on carbon surface

ICP-OES (wt%)[b]Hybrid CatalystElectrochemistry[a]

(mol cm-2)TGA[b] (wt%)

Batch 1 Batch 2

[GC-2Rh(CO)2] 3.4 x 10-10 - - -

[CB-2Rh(CO)2] - 2.57 3.29 2.47

[G-2Rh(CO)2] - 1.32 1.05 0.84

[a] amount of Rh on 2.4 cm2 glassy carbon electrode (mol). [b] Amount of Rh per total mass of carbon black or graphene (wt%).

18

Calculations of total weight losses of complex immobilized on CB and G

Total weight loss calculated from graph for [CB-2Rh(CO)2] from 100 °C to 490 °C

=% weight at 100 °C - % weight at 490 °C (assumption: there is hardly any change in the weight loss of the unmodified carbon black)

= 98.2-85.4 = 12.8%

Total weight loss calculated from graph for [G-2Rh(CO)2] from 350 °C to 650 °C (assumption: both unmodified graphene and [G-2Rh(CO)2] had similar weight losses from 100 °C to 350 °C, after 650 °C a very slight change in the slope of graph is observed, assuming another process is happening (decomposition of carbon))

= [(% weight of [G-2Rh(CO)2] - % weight loss of unmodified graphene) at 350 °C] - [(% weight loss of [G-2Rh(CO)2] - % weight loss of carbon black) at 490 °C]

= (88.6-58.3)-(88.6-64.8) = 6.58%

Example calculations of amount of Rhodium (wt%) on CB

From TGA weight loss, example calculation of amount of Rhodium (wt%) on carbon black is as follows:

For [CB-2Rh(CO)2], from TGA, total weight loss is 13%.

19

Amount in mass loss from 0.537 mg weight of sample used for TGA

= 13/100 x 0.537 = 0.069 mg

Assuming all mass loss is due to the covalently attached rhodium complex.

Amount of Rh complex on the carbon black surface

= mass loss/molecular weight of Rh complex

= 0.069 mg/513.07g mol-1 = 0.00013 mmol

Mass of Rh metal on surface

= (amount of Rh complex=amount of Rh metal) x atomic weight of Rh = 0.00013 mmol x 102.9 g mol-1

= 0.0014 mg

Hence, amount of Rh (wt%) on carbon black for [CB-2Rh(CO)2]

= 0.0014/0.537 x 100 = 2.57 wt%

Figure S12. TGA curves for unmodified CB, [CB-2Rh(CO)2], [2Rh(CO)2]BPh4 and CB mix and [2Rh(CO)2]BPh4 recorded under an atmosphere of nitrogen.

20

S4. Inductively Coupled Plasma (ICP-OES) or Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The Rh content in the immobilized catalyst was determined using ICP-OES or ICP-MS using a PerkinElmer NexIon 300D instrument. The catalyst sample was digested in a mixture of refluxing H2SO4 (2 mL) and HNO3 (4 mL) following a literature procedure.1 The black mixture becomes a clear orange solution mixture. After cooling to room temperature, aqua regia (HCL (3 mL):HNO3 (1 mL), 4 mL) was added slowly dropwise to the mixture. After complete addition, the mixture was heated until boiling for 1-2 hours, at which time the mixture turns pale yellow or colourless. The mixture was then cooled to room temperature and transferred to a volumetric flask and made up to 25 mL with MIliQ water.

Table S12. Summary of ICP-OES or ICP-MS of [G-2Rh(CO)2] and [CB-2Rh(CO)2] before and after each catalysis run during recycling experiments.

Entry Hybrid Catalyst Catalysis Run ICP-MS (µg L-1)

ICP-OES (mg L-1) Rh wt%

1 0 421 - 0.622 1 87.4 - 0.603 2 53.7 - 0.594

Recycling Experiments

3 34.5 - 0.585

NN

NN

NRh

CO

CO

Mes X

[G-2Rh(CO)2]Catalyst used at

0.02 mol% 0 - 0.35 0.84

6 0 - 3.03 3.37 1 - 1.72 2.98 2 - 0.23 2.89

Recycling Experiments

3 - 0.31 2.810 CB

NN

NN

NRh

CO

CO

Mes X

[CB-2Rh(CO)2]Catalysts used at

0.02 mol% 0 - 2.30 2.5

Example of calculation for entry 1:

mRh = 0.421 mg/L × 0.025 L = 0.0105 mg;

Rh wt % = (0.0105/1.7) × 100% = 0.62 wt%.

21

SI-5. Electrochemistry. Calculations for surface coverage of Rh complex on [GC-2Rh(CO)2].

Cyclic voltammetry (CV) was performed using an Autolab PGSTAT 302N potentiostat (Eco Chemie, Netherlands) which was interfaced with computers and data was outputted with Nova 1.11 software. A conventional three-electrode system was employed, with the working electrode [GC-2Rh(CO)2], the platinum rod counter electrode from Echo Chemie (Netherlands) and the leakless Ag/AgCl reference electrode from eDAQ (Australia).

The glassy carbon electrode was prepared similarly to the procedure stated in section SI-1 under immobilization of [GC-2Rh(CO)2]. The cyclic voltammetry was performed in 5 mL of electrolyte (0.1M [Bu4N][PF6] in CH2Cl2), which was then scanned between +1.5 to -1 V at 100 mV s-1. Measurements began at 0 V with an anodic sweep. The leakless Ag/AgCl reference electrode was calibrated externally to be -0.625 V against ferrocene/ferrocenium couple in the same supporting electrolyte and solvent.

-1.0 -0.5 0.0 0.5 1.0 1.5

-0.0003

-0.0002

-0.0001

0.0000

0.0001

Cur

rent

(A)

Potential (V)

Figure S13. Cyclic voltametry of [GC-2Rh(CO)2] as the working electrode in 0.1M [Bu4N][PF6]/CH2Cl2, 100 mV s-1.

Experimental surface coverage based on graph above:

surface coverage Γ = Q/nFA

Q = charge = integrated peak area/scan rate = 1.6 x 10-6 VA/0.1 Vs-1 = 1.6 x 10-5 C

22

n = the number of electrons employed in the electrochemical reaction (for the oxidation Rh(I) to Rh(II)) = 1

F = Faraday's Constant = 96490 C mol-1

A = area of electrode used = 1/2 of 2.4 cm2 electrode = 1.2 cm2

Hence, surface coverage per area of 1.2 cm2 electrode, Γ = Q/nFA = 1.6 x 10-5/(1 x 96490 x 1.2) = 1.4 x 10-10 mol cm-2

Surface coverage of Rh molecules for 2.4 cm2 glassy carbon electrode

= 1.4 x 10-10 mol cm-2 x 2.4 = 3.4 x 10-10 mol cm-2

Theoretical surface coverage based on size of structure

Assumed that the molecule takes up a space as a circle due to the way the molecule seems to orient itself,

Average possible diameter = (7.85+6.764)/2 = 7.307 Å

Area of circular area = πr2 = π x (7.307/2)2 = 42 Å2 = 4.2 x 10-19 m2

Estimated amount of molecules occupying 1.2 cm2 of electrode

= (0.00012 m2/4.2 x 10-19 m2) = 2.9 x 1014

Number of moles of molecules = N/NA = 5.7 x 1014/6.023 x 1023 = 4.7 x 10-10 moles

Coverage of molecules per surface area of 1.2 cm2 of the electrode = 4.7 x 10-10/1.2 = 4.0 x 10-10 mol cm-2

Theoretical surface coverage of Rh molecules on 2.4 cm2 surface area of glassy carbon electrode = 4.0 x 10-10 mol cm-2 x 2.4 = 9.6 x 10-10 mol cm-2

23

SI-6. Infrared Spectroscopy (FTIR). The FTIR analyses were carried out on PerkinElmer FTIR Spectrometer equipped with a diamond attenuated total reflectance (ATR) imaging crystal available for fast imaging at 1.56 micron spatial resolution. FTIR spectra were recorded in the wavenumber range between 4000 and 100 cm−1, averaging 4 scans per sample. The Spectrum software was used for data collection and to process and analyze the data. The homogenous complex was placed directly onto the crystal surface to obtain the IR spectrum. The carbon samples were ground up with KBr (1:10 by weight) and the mixture was placed directly onto the crystal surface. A background spectrum was recorded with the press in the down position.

4000 3500 3000 2500 2000 1500 1000

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Tran

smitt

ance

(a.u

.)

Wavenumber (cm-1)

[2Rh(CO)2]BPh4

[G-2Rh(CO)2] unmodified graphene (G)

Figure S14. IR spectra for unmodified graphene (G, black trace), graphene modified with Rh complex ([G-2Rh(CO)2], red trace) and homogeneous catalyst ([2Rh(CO)2]BPh4, blue trace).

2 x CO stretching peaks corresponding to the carbonyl groups in ([2Rh(CO)2]BPh4

24

4000 3500 3000 2500 2000 1500 1000

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Tran

smitt

ance

(a.u

.)

Wavenumber (cm-1)

[2Rh(CO)2]BPh4

[G-2Rh(CO)2] unmodified graphene (G)

Figure S15. IR spectra for unmodified carbon black (CB, black trace), carbon black modified with Rh complex ([CB-2Rh(CO)2], red trace) and homogeneous catalyst ([2Rh(CO)2]BPh4,

blue trace).

2 x CO stretching peaks corresponding to the carbonyl groups in ([2Rh(CO)2]BPh4

25

SI-7. Raman Spectroscopy. Raman spectroscopy was performed on an inVia Renishaw Raman microscope using green (514 nm) laser excitation. Scans were taken on an extended range (100–3200 cm−1), the exposure time was 60 s and the power was set at 25 mW. Samples were briefly sonicated in acetone and drops applied to a glass slide for observation. The sample was viewed using a green laser apparatus under a maximum magnification of ×50.

500 1000 1500 2000 2500 30000.0

0.2

0.4

0.6

0.8

1.0

Inte

nsity

(a.u

.)

Raman Shift (cm-1)

unmodified graphene (G) [G-2Rh(CO)2]

Figure S16. Raman spectra of unmodified graphene (black trace) and [G-2Rh(CO)2] (red trace).

slight increase in the intensity of the defects (D) band

26

1000 2000 30000.0

0.2

0.4

0.6

0.8

1.0In

tens

ity (a

.u.)

Raman Shift (cm-1)

unmodified carbon black (CB) [CB-2Rh(CO)2]

Figure S17. Raman spectra of unmodified carbon black (blue trace) and [CB-2Rh(CO)2] (green trace).

Table S13. Ratio of peak intensity for the defects (D) and graphite (G) bands observed in the Raman spectra.

sample I(D)/I(G)unmodified graphene 0.79

[G-2Rh(CO)2] 0.82unmodified carbon black 0.92

[CB-2Rh(CO)2] 1.0

slight increase in the intensity of the defects (D) band

27

S8. Scanning Electron Microscopy (SEM). SEM images of unmodified graphene and [G-2Rh(CO)2] were obtained using a Hitachi S3400 SEM instrument. Samples were prepared by dispersing the solid unmodified graphene and [G-2Rh(CO)2] samples in ethanol and dropping the mixture on a clean aluminium disc and allowed to air-dry. After drying the powders on the mount, the sample was then vacuum coated with chromium to eliminate charge effect.

1. Unmodified graphene

Figure S18. (a), (b), (c) and (d) SEM images of different regions of the unmodified

graphene sample at different magnifications, highlighting the extensive morphology and 2D

nature of the graphene formation. Scale bars indicate (a) 20.0 µm, (b) 10.0 µm, (c) 20.0 µm

and (d) 10.0 µm.

(a) (b)

(c) (d)

28

2. [G-2Rh(CO)2]

Figure S19. (a), (b), (c) and (d) SEM images of different regions of a [G-2Rh(CO)2] sample

at different magnifications, highlighting the similarity in morphology of the [G-2Rh(CO)2]

to the unmodified graphene (Figure S17) even after treatment for immobilisation of the Rh

complex. Scale bars indicate (a) 10.0 µm, (b) 10.0 µm, (c) 20.0 µm and (d) 10.0 µm.

(a) (b)

(c)

(d)

29

SI-9. Transmission Electron Microscopy (TEM). TEM images of unmodified graphene and [G-2Rh(CO)2] was obtained using a FEI Tecnai G2 20 TEM instrument. Samples were prepared by dispersing the solid unmodified graphene and [G-2Rh(CO)2] samples in ethanol and dropping the mixture on a clean copper plate and allowed to air-dry.

1. Unmodified graphene

Figure S20. (a), (b), (c) and (d) TEM images of different regions of the unmodified

graphene sample at different magnifications, highlighting the 2D nature of the graphene and

the overlapping stacking conformation of the 2D graphene sheets. Scale bars indicate (a)

0.5 µm, (b) 1.0 µm, (c) 0.5 µm and (d) 0.5 µm.

(a) (b)

(c) (d)

(c) (d)

30

2. [G-2Rh(CO)2]

Figure S21. (a), (b), (c) and (d) TEM images of different regions of the [G-2Rh(CO)2]

sample at different magnifications, highlighting the 2D nature of the graphene and the

overlapping stacking conformation of the 2D graphene sheets, similar to what we observed

for the unmodified graphene (Figure S19) even after treatment for immobilisation of the Rh

complex. Scale bars indicate (a) 0.5 µm, (b) 1.0 µm, (c) 1.0 µm and (d) 1 µm.

(c) (d)

31

PhPh

[catalyst]Et3SiH (2 eq.)

THF Et3Si

PhPh

H4 5

Ph H

Et3Si Ph6

not formed

SI-10. Catalysis and Recycling Experiments

Table S14. Full details for the hydrosilylation of diphenylacetylene 4 with triethylsilane

catalyzed by immobilized and homogeneous catalysts

No. Catalyst mol%Temp.

(°C)

Conv.

(%)[a]

Time

(h)TON[b]

1

GC

NN

NN

NRh

CO

CO

Mes

[GC-2Rh(CO)2]

1.7 x 10-4 50 8 48 48000

2 1.6 [b] 50 >98 24 61

3 50 >98 0.25 5400

4 25 77 1 4200

5 CB

NN

NN

NRh

CO

CO

Mes

[CB-2Rh(CO)2]

0.02

25 >98 2 5600

6Carbon black

only (XC-72R)- 50 0 24 -

32

7 0.3[c] 50 >98 24 320

8 3.6 0.25 180

9 56 0.5 2700

10

NN

NN

NRh

CO

CO

Mes

[G-2Rh(CO)2]

0.02 50

>98 1 5200

11 Graphene only - 50 0 24 -

12

Graphene +

[1Rh(COD)]BPh4

after similar

treatment

- 50 0.08 24 -

13 0.5 50 >98 <0.08 200

14 50 >98 0.25 4400

15 33 0.5 2000

16

NN

NN

NRh

CO

CO

Mes BPh4

[2Rh(CO)2]BPh4

0.0225

>98 1 4500

17 No catalyst - 50 0 24 -

[a] Determined using 1H NMR spectroscopy; [b] TON = turnover number = [amount

of product formed at that time]/[amount of catalyst used]; [c] 1st batch of [CB-

2Rh(CO)2] with Rh amount by ICP of 3.29 wt%;[d] 1st batch of [G-2Rh(CO)2] with

Rh amount by ICP of 0.62 wt%

33

Table S15. Full details of recycling experiments with [GC-2Rh(CO2)], [CB-2Rh(CO2)] and [G-2Rh(CO2)].

[GC-2Rh(CO)2] [CB-2Rh(CO)2] [G-2Rh(CO)2]

Entry%Conv(48 h)

Ratio N:Rh[a]

%Conv.

(24 h)

wt% Rh[b]

(% recovered catalyst)[c]

%Conv.

(24 h)

wt% Rh[b]

(% recovered catalyst) [c]

Before recycling

- 4.5 - 3.3[d] (100) - 0.62[e] (100)

After cycle 1

7.6 4.5 >98 2.9 (88) >98 0.60 (97)

After cycle 2

11.0 4.5 >98 2.8 (85) >98 0.59 (95)

After cycle 3

2.0 4.7 >98 2.8 (85) >98 0.58 (94)

[a] Ratio of N:Rh obtained by XPS of GC surface; [b] % wt Rh on carbon surface by ICP-

MS; [c] % recovered catalyst (Rh(I) complex and carbon surface); [d] 1st batch of [CB-

2Rh(CO)2] with Rh amount by ICP of 3.29 wt%; [e] 1st batch of [G-2Rh(CO)2] with Rh

amount by ICP of 0.62 wt%.

34

Figure S22. Graph showing the recyclability of the homogeneous catalyst [2Rh(CO)2]BPh4 for 5 cycles at 25°C. The recycling was performed by batchwise addition of the substrates diphenylacetylene (0.3 mM) and triethylsilane (0.6 mM) for 5 consecutive times into the reaction mixture containing the [2Rh(CO)2]BPh4 (2 mol%) in tetrahydrofuran (0.6 mL). The reaction mixture was analyzed by NMR.

Table S16. List of % conversions obtained for 10 cycles of recycling experiments with [CB-2Rh(CO2)] and [G-2Rh(CO2)]. Each cycle was tested over 4h at 25 °C.

% ConversionCatalysis Cycle [CB-2Rh(CO)2] [G-2Rh(CO)2]

1 >98 >982 >98 >983 >98 >984 >98 >985 >98 >986 >98 >987 94 >988 81 969 89 >9810 71 >98

35

SI-11. References

1. M. Perez-Cadenas, L. J. Lemus-Yegres, M. C. Roman-Martinez and C. Salinas-Martinez de Lecea, Applied Catalysis, A: General, 2011, 402, 132-138.