Supporting Information Ruthenium nanoparticles supported on carbon ...
Supporting Information Ruthenium nanoparticles supported on carbon - an active catalyst for the hydrogenation of lactic acid to 1,2-propanediol Sarwat Iqbal,a Simon A. Kondrat,a Daniel R. Jones,a Daniël Schoenmakers,a Jennifer K. Edwards,a Li Lu,b Benjamin R. Yeo,a Peter P. Wells,c Emma K. Gibson,c David J. Morgan,a Christopher J. Kielyb and Graham J. Hutchingsa,* *[email protected] a
Cardiff Catalysis Institute, School of Chemistry, Main Building, Cardiff University, Park
Place, Cardiff, CF10 3AT, UK b
Department of Materials Science and Engineering, Lehigh University, 5 East Packer
Avenue, Bethlehem, PA 18015-3195, USA c
The UK Catalysis Hub, Research Complex at Harwell, Harwell, Oxon, OX11 0FA, UK and,
Kathleen Lonsdale Building, Department of Chemistry, University College London, Gordon Street, London, WC1H 0AJ, UK
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List of Contents 1. BET surface areas of catalysts 2. Porosimetry measurements 3. Powder X-ray diffraction analysis 4. Temperature programmed reduction studies 5. X-ray Photoelectron spectroscopy of pre-reduced catalysts
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1. BET surface areas of catalysts Table S1. BET surface area measurements of Ru supported on different carbons. Carbon/catalyst G-60 XC72R-WI XC72R-SI GCN 3070 Commercial ROX0.8
Surface area (m2/g) 5% Ru/C carbon 650 655 204 213 200 213 580 586 835 489 495
2. Porosimetry measurements In order to get a better understanding of the structure of the most active catalysts, porosimetry determinations were carried out on the commercial Ru/C material and the Ru/CXC72R-SI catalyst (prepared by sol immobilization). Their profiles are shown in Figures S1 and S2 respectively, and the corresponding quantitative data derived from these plots is summarized in Table S2.
a
b
Figure S1. Pore size distribution of commercial Ru/C catalyst – a) Isotherm data, b) cumulative pore volume (grey) and pore size distribution (blue)
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Figure S2. Ru/C XC72R-SI catalyst – Isotherm data
a
b
Figure S3. Pore size distribution of the Ru/C XC72R-SI catalyst- cumulative pore volume (grey) and pore size distribution (blue) . Figure b) is a magnified view of (a) within the 0200 A range.
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There is no documentation available for the type of carbon used for the commercial catalyst, but there is clearly a difference in the pore size of both catalysts. A combination of microand meso- porosity is observed in the Ru/C XC72R-SI catalyst (Figure S2 and 3). Adsorption of nitrogen on the commercial Ru/C catalyst resulted in the formation of a type 1 isotherm which is typical of microporous materials (Figure S1,). The commercial catalyst also has a very high surface area and very low pore size (Table S2), while the overall pore volume is not too different from that of the Ru/C XC72R-SI material. Table S2. Porosity measurements for the Ru/C XC72R-SI and commercial Ru/C catalysts.
Average pore size (A) Pore volume (cc/g) BET (m2/g)
XC72R-SI 402 0.519 202
Commercial Ru/C 6 0.669 850
Table S3. BET surface area (m2/g) for the Ru/C XC72R-SI and commercial Ru/C used catalysts.
1st reuse 2nd reuse 3rd reuse
XC72R-SI (m2/g) 196 188 182
5
Commercial Ru/C (m2/g) 842 835 832
3. Powder X-ray diffraction analysis
Intensity
G60 XC72R-WI ROX 0.8 XC72R-SI Graphene oxide GCN3070 commercial
0
10
20
30
40
50
60
70
80
90
Diffraction angle/2θ
Figure S4. Comparison of XRD spectra from the Ru/C commercial catalyst with all the various ‘in-house’ prepared catalysts. XRD patterns of the catalysts prepared with Ru on different carbon supports are very similar to the bare carbons (see Figure S5). There were no ruthenium phases identified in any of these catalysts.
6
20000
GCN3070
Intensity (a.u.)
15000
ROX0.8 10000
XC72R G60
5000
Graphene oxide 0 10
20
30
40
50
Diffraction angle/ 2θ
Figure S5. XRD patterns of the various bare carbon supports
7
60
70
80
4. Temperature programmed reduction studies
Detector signal (mv)
2500
a
2000
b
1500
1000
500
d
c
e
f
0 100
200
300
400
Temperature°C
Figure S6. TPR profiles of the various 5 wt% Ru/C catalysts a) Commercial 5 wt% Ru/C material; b) 5 wt% Ru /GCN3070; c) 5 wt% Ru /XC72R-SI; d) 5 wt% Ru/G60; e) 5 wt% Ru/ROX0.8, and f) 5 wt% Ru /XC72R-WI.
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Detector signal (mv)
10000
8000
6000
4000
2000
Graphene oxide
0 0
50
100
150
200
250
300
350
400
Temperature (°C)
Figure S7. – TPR profiles of the 5wt% Ru/graphene oxide sample. TPR data confirms that reduction of the Ru species on the surface prior to the reaction– be it Ru(II) or higher oxidation states – are fully reduced at temperatures above 120oC (excepting 5%Ru/graphene oxide, which is an inactive catalyst) confirming that the active Ru species under the reaction conditions is a lower oxidation state. None of the catalysts were reduced prior to our catalytic testing experiments, hence we expect that all the catalysts, apart from the one supported on graphene oxide, will be reduced during the initial phase of the reaction which takes place at 120oC under 35 bar H2. This may account for the abnormally low catalyst activity exhibited by the graphene oxide-supported catalyst where the lactic acid hydrogenation temperature is always kept below the reduction temperature of 150oC needed for Ru reduction on the GO surface.
5. X-ray photoelectron spectroscopy of pre-reduced catalysts
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(c)
(c)
(b)
(b)
(a)
(a)
Figure S8. – O(1s) and Ru(3d)/C(1s) core-level spectra of (a) fresh, (b) pre-reduced, (c) x1 use (after reduction) of the commercial 5wt% Ru/C catalyst.
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(c)
(b)
(a)
Figure S9. – Ru(3p) core-level spectra of (a) fresh and (b) pre-reduced commercial 5wt% Ru/C catalyst, (c) subtraction of spectra (b-a)
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Cardiff Catalysis Institute, School of Chemistry, Main Building, Cardiff University, Park
Place, Cardiff, CF10 3AT, UK b
Department of Materials Science and Engineering, Lehigh University, 5 East Packer
Avenue, Bethlehem, PA 18015-3195, USA c
The UK Catalysis Hub, Research Complex at Harwell, Harwell, Oxon, OX11 0FA, UK and,
Kathleen Lonsdale Building, Department of Chemistry, University College London, Gordon Street, London, WC1H 0AJ, UK
1
List of Contents 1. BET surface areas of catalysts 2. Porosimetry measurements 3. Powder X-ray diffraction analysis 4. Temperature programmed reduction studies 5. X-ray Photoelectron spectroscopy of pre-reduced catalysts
2
1. BET surface areas of catalysts Table S1. BET surface area measurements of Ru supported on different carbons. Carbon/catalyst G-60 XC72R-WI XC72R-SI GCN 3070 Commercial ROX0.8
Surface area (m2/g) 5% Ru/C carbon 650 655 204 213 200 213 580 586 835 489 495
2. Porosimetry measurements In order to get a better understanding of the structure of the most active catalysts, porosimetry determinations were carried out on the commercial Ru/C material and the Ru/CXC72R-SI catalyst (prepared by sol immobilization). Their profiles are shown in Figures S1 and S2 respectively, and the corresponding quantitative data derived from these plots is summarized in Table S2.
a
b
Figure S1. Pore size distribution of commercial Ru/C catalyst – a) Isotherm data, b) cumulative pore volume (grey) and pore size distribution (blue)
3
Figure S2. Ru/C XC72R-SI catalyst – Isotherm data
a
b
Figure S3. Pore size distribution of the Ru/C XC72R-SI catalyst- cumulative pore volume (grey) and pore size distribution (blue) . Figure b) is a magnified view of (a) within the 0200 A range.
4
There is no documentation available for the type of carbon used for the commercial catalyst, but there is clearly a difference in the pore size of both catalysts. A combination of microand meso- porosity is observed in the Ru/C XC72R-SI catalyst (Figure S2 and 3). Adsorption of nitrogen on the commercial Ru/C catalyst resulted in the formation of a type 1 isotherm which is typical of microporous materials (Figure S1,). The commercial catalyst also has a very high surface area and very low pore size (Table S2), while the overall pore volume is not too different from that of the Ru/C XC72R-SI material. Table S2. Porosity measurements for the Ru/C XC72R-SI and commercial Ru/C catalysts.
Average pore size (A) Pore volume (cc/g) BET (m2/g)
XC72R-SI 402 0.519 202
Commercial Ru/C 6 0.669 850
Table S3. BET surface area (m2/g) for the Ru/C XC72R-SI and commercial Ru/C used catalysts.
1st reuse 2nd reuse 3rd reuse
XC72R-SI (m2/g) 196 188 182
5
Commercial Ru/C (m2/g) 842 835 832
3. Powder X-ray diffraction analysis
Intensity
G60 XC72R-WI ROX 0.8 XC72R-SI Graphene oxide GCN3070 commercial
0
10
20
30
40
50
60
70
80
90
Diffraction angle/2θ
Figure S4. Comparison of XRD spectra from the Ru/C commercial catalyst with all the various ‘in-house’ prepared catalysts. XRD patterns of the catalysts prepared with Ru on different carbon supports are very similar to the bare carbons (see Figure S5). There were no ruthenium phases identified in any of these catalysts.
6
20000
GCN3070
Intensity (a.u.)
15000
ROX0.8 10000
XC72R G60
5000
Graphene oxide 0 10
20
30
40
50
Diffraction angle/ 2θ
Figure S5. XRD patterns of the various bare carbon supports
7
60
70
80
4. Temperature programmed reduction studies
Detector signal (mv)
2500
a
2000
b
1500
1000
500
d
c
e
f
0 100
200
300
400
Temperature°C
Figure S6. TPR profiles of the various 5 wt% Ru/C catalysts a) Commercial 5 wt% Ru/C material; b) 5 wt% Ru /GCN3070; c) 5 wt% Ru /XC72R-SI; d) 5 wt% Ru/G60; e) 5 wt% Ru/ROX0.8, and f) 5 wt% Ru /XC72R-WI.
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Detector signal (mv)
10000
8000
6000
4000
2000
Graphene oxide
0 0
50
100
150
200
250
300
350
400
Temperature (°C)
Figure S7. – TPR profiles of the 5wt% Ru/graphene oxide sample. TPR data confirms that reduction of the Ru species on the surface prior to the reaction– be it Ru(II) or higher oxidation states – are fully reduced at temperatures above 120oC (excepting 5%Ru/graphene oxide, which is an inactive catalyst) confirming that the active Ru species under the reaction conditions is a lower oxidation state. None of the catalysts were reduced prior to our catalytic testing experiments, hence we expect that all the catalysts, apart from the one supported on graphene oxide, will be reduced during the initial phase of the reaction which takes place at 120oC under 35 bar H2. This may account for the abnormally low catalyst activity exhibited by the graphene oxide-supported catalyst where the lactic acid hydrogenation temperature is always kept below the reduction temperature of 150oC needed for Ru reduction on the GO surface.
5. X-ray photoelectron spectroscopy of pre-reduced catalysts
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(c)
(c)
(b)
(b)
(a)
(a)
Figure S8. – O(1s) and Ru(3d)/C(1s) core-level spectra of (a) fresh, (b) pre-reduced, (c) x1 use (after reduction) of the commercial 5wt% Ru/C catalyst.
10
(c)
(b)
(a)
Figure S9. – Ru(3p) core-level spectra of (a) fresh and (b) pre-reduced commercial 5wt% Ru/C catalyst, (c) subtraction of spectra (b-a)
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