Area of Interest:

Designing efficient materials for

photocatalytic conversion of CO2

HARIPRASAD NARAYANAN

NATIONAL CENTRE FOR CATALYSIS RESEARCH

INDIAN INSTITUTE OF TECHNOLOGY, MADRAS

Photocatalytic Reduction of Carbon Dioxide

Photocatalytic Reduction of Carbon Dioxide

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©2016 JCAPhttp://solarfuelshub.org/why-solar-fuels

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©2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Adv.Mater., 2015, 27, 1957–1963.

Gaseous phase reduction

Liquid phase reduction or carbonate pathway

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Environmental Chemistry by Colin Baird , ©2012 W.H Freemanhttps://en.wikipedia.org/wiki/Carbon_dioxide

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NCurr. Opin. Biotechnol. 2010 Jun;21(3):298-310, © 2010 Elsevier

©2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

©2013 BASF

Adv.Mater., 2015, 27, 1957–1963.

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LEnergy Environ. Sci., 2016,9, 2177-2196 ©2016 The Royal Society of Chemistry

Environmental Chemistry by Colin Baird , ©2012 W.H Freeman

Anal. Methods, 2013,5, 1086-1097

Reaction pH 0 pH7 pH14

E0 (V vs NHE)

+0.169 -0.24 -0.65

+0.030 -0.39 -0.79

-0.071 -0.55 -0.89

-0.103 -0.51 -0.93

-0.199 -0.58 -1.02

-0.425 -0.888 -1.29

-0.103 -0.52 -0.93

If the first electron transfer to the CO2 reduction

needs such a high overpotential up to -1.9 V vs NHE

at pH 0, then how would be the reduction reaction

taking place in the semiconductors with a reduction

potential far less than required?

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Energy Environ. Sci., 2016,9, 2177-2196 ©2016 The Royal Society of Chemistry

Carbon Dioxide and Organometalics, Xiao-Bing Lu©2016 Springer

Carbon Dioxide Radical Anion I

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Reaction Mechanisms in Carbon Dioxide Conversion ,Aresta, Michele, Dibenedetto, Angela,

Quaranta, Eugenio ©2016 Springer

Catalyst modifications like doping, metal

deposition, use of sacrificial reagents etc. does

not change the position of conduction band

towards more negative. Then, how these

modifications give rises to more products yield

(marginal yield only) compared to the bare

photocatalytic material?

Advances in CO2 conversion and utilization, Yun Hang Hu, 2010

Sacrificial Reagents

Reactive Oxygen Species

Photocatalysis and Water Purification by Pierre Pichat©2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The new cobalt catalyst also splits water into hydrogen

and oxygen without creating the kind of reactive oxygen

molecules that can damage DNA or other processes

essential to continuing life. "I don't know why yet," Nocera

says. "That will be fun to figure out."

Fate of insitu reduction products

J. Phys. Chem. Lett., 2013, 4 (20), pp 3479–3483

Reaction Pathways

Angew. Chem. Int. Ed. 2013, 52, 7372 – 7408©2013 WILEY-VCH Verlag

GmbH & Co. KGaA, Weinheim

Novel Materials for Carbon

Dioxide Mitigation

Technology, 1st Edition

©2013 Elsevier

CARBON DIOXIDE REDUCTION OR ACTIVATION ?

Do we need to be concerned on the

activation of carbon dioxide?

or

Its subsequent reaction with hydrogen for

the formation of value added chemicals?