A ruthenium trinuclear polyazine complex was synthesized and subsequently immobilized through complexation to a graphene oxide support containing phenanthroline ligands (GO-phen). The developed photocatalyst was used for the photocatalytic reduction of CO2 to methanol, using a 20 watt white cold LED flood light, in a dimethyl formamide–water mixture containing triethylamine as a reductive quencher. After 48 h illumination, the yield of methanol was found to be 3977.57
5.60 mmol gcat 1. The developed photocatalyst exhibited a higher photocatalytic activity than graphene oxide, which provided a yield of 2201.40
8.76 mmol gcat 1. After the reaction, the catalyst was easily recovered and reused for four subsequent runs without a significant loss of catalytic activity and no leaching of the metal/ligand was detected during the reaction.

1. Development of novel catalytic systems for photoreduction of CO2
to fuel and chemicals
Supervisor: Dr. Bir Sain,
Co-Supervisor: Dr. Suman L. Jain*
1

2. Introduction
 Global energy consumption was 15–17 TW in 2010 and will increase to 25–27
TW by 2050.
 81% of the energy needs were met by fossil fuels, while renewable sources
accounted for 13% in 2011.
If we can capture 10% of the solar energy falling on 0.3% of the land surface it
will be suffice for meeting our energy demand in 2050.
The CO2 global average concentration in Earth's atmosphere was increased from
270 ppm in 1958 to 395 ppm in 2012.
Photocatalytic conversion of this greenhouse gas into valuable products can
provide energy in a sustainable way with levelling off the concentration of CO2 in
our environment.
2

3. Scope of present study
• In the current study we have synthesized graphene oxide attached Ruthenium
trinuclear complex
• Characterization of synthesized catalyst was done with FTIR, 1H NMR, 13C
NMR, ESI-HRMS, XPS, XRD, SEM, TEM, ICP-AES, UV-VIS, BET and CO2
photo reduction product was analysed with GC-FID and.
• The developed photocatalyst was visible light active and exhibited
significantly higher catalytic activity and selectivity to give methanol yield
3977.57±5.60 μmol.g-1 cat after 48h in presence of sacrificial donor (Triethyl
amine). While GO show methanol yield 2201.40±8.76 μmol.g-1 cat.
•Standard error was measured by three measurements
• Possible mechanism for conversion of CO2 to methanol with catalyst was
proposed on the basis of band gap difference.
3

4. Step-wise synthesis of Ruthenium trinuclear complex attached GO catalyst
a) Synthesis of Ru trinuclear complex 1
b) Attachment of Ru complex 1 to GO
4

5. Characterization :
SEM Image of a) GO, b) GO attached Ru complex2
and EDX pattern of 2
1H NMR of Ru trinuclear complex 1
13C NMR of Ru trinuclear complex 1
ESI-HRMS of Ru trinuclear complex 1
5

6. XRD Pattern
TEM Image of a) GO b) GO-Ru complex2 c) SAED
UV Absorbance
XPS spectra a) survey scan of GO-Ru comp 2, b) C(1s) and Ru (3d)
IR Spectra
6

7. C% H% N% Ru%
56.13 3.20 4.43 4.14
DT-TGA
Adsorption desorption isotherm
Pore size distribution of a) GO, b) GO-Ru catalyst2
Tauc plot for calculating band gap of GO
CHN and ICP-AES analysis of catalyst
7

8. Calibration curve for quantitative
determination of methanol
GC chromatogram image of photoreaction product
Reaction Illumination condition
Quantification of photoreaction
8

9. Methanol formation rate
Recycling experiment
GC-Mass of product a) using 12CO2, b) using 13CO2
Ru%
4.12
ICP-AES
after recycling
9

10. e
e
e
e
e
CB
VB
e
2.9–3.7eV
MLCT
10

11. Conclusion :
• We have developed a highly efficient graphene oxide attached Ru
trinuclear visible light active photoredox catalyst for photoreduction of
CO2 to methanol.
• The developed photocatalyst exhibited higher catalytic activity than
graphene oxide alone.
•The developed catalyst was found to be selective and afforded
methanol as the major reaction product.
• Covalent attachment of the Ru-complex to GO support provided
stability and the developed photocatalyst did not show any significant
leaching during the reaction.
•The developed catalyst yielded 3977.57±5.60 μmol/gcat methanol and
was successfully reused for subsequent runs.
11

12. References:
1. A. Fujishima; K. Honda Nature 1972, 238, 37–38.
2. A. J. Morris, G. J. Meyer, E. Fujita; Acc. Chem. Res. 2009, 42, 1983-1994.
3. M. Ni, M. K. H. Leung, D. Y. C. Leung; K. Sumathy Renew. Sustain. En. Rev. 2007, 11,
401–425
4. D. Dvoranová; V. Brezová; M. A. Malati App. Catal. B: Env. 2002, 37, 91‐105.
5. X. Chen; S. S. Mao Chem. Rev. 2007,107, 2891‐2959.
6. C.-J. Li, J.-N. Wang, B. Wang, J. R. Gong, Z. Lin Mater. Res. Bull. 2012, 47, 333–337
7. R. B. N. Baig; R. S. Varma Chem. Commun., 2013, 49, 752
8. Z. Guo, C. Shao, M. Zhang, J. Mu, Z. Zhang, P. Zhang, B. Chen, Y. Liu J. Mater. Chem.,
2011, 21, 12083
9. M. Kobayashi, S. Masaoka, K. Sakai Molecules 2010, 15, 4908-4923
10. Z. Guo, C. Shao, M. Zhang, J. Mu, Z. Zhang, P. Zhang, B. Chen, Y. Liu J. Mater. Chem.,
2011,21, 12083
11. A. Rezaeifard, M. Jafarpour, A. Naeimi; R. Haddad Green Chem. 2012, 14, 3386
12. B. Karimi, E. Farhangi Chem. Eur. J. 2011, 17, 6056 – 6060
13. G. Das, B. Sain, S. Kumar, M.O.Garg, G. Murali Dhar Catal. Today 2009, 141, 152-156
14. M. Kobayashi, S. Masaoka, K. Sakai Molecules 2010, 15, 4908-4923
15. W. Haung, T. Ogawa Polyhedron, 2006, 25, 1379-1385.
16. J. Kim, J. Kim, M. Lee;; Surf. Coat. Technol; 2010, 205, 372–376
17. X.X. Yu, S.W. Liu, J.G. Yu Appl. Catal. B: Environ 2011, 104 , 12–20
18. J. Wang, X. Liu, R. Li, P. Qiao, L. Xiao, J. Fan Catal. Comm. 2012, 19, 96–99
12