2016_15: Electro-Catalytic Fixing of Carbon Dioxide
into Chemicals
Supervisors: Dr George Britovsek (g.britovsek@imperial.ac.uk), Professor
Anthony Kucernak (Chemistry), Professor Geoff Kelsall (Chemical Engineering)
Department: Chemistry
Climate change mitigation and zero-carbon production systems will rely on the
development of efficient methods to capture and fix / utilise CO2. The 8-10 % penalty
in chemical-to-electrical energy conversion efficiencies of coupling conventional
carbon capture and storage (CCS) to fossil-fuelled power stations, makes carbon
capture and utilisation (CCU) a more attractive option, converting CO2 into fuels or
chemicals.1 Hence, this project will develop the electro-catalytic reduction of CO2 in
combination with alkenes to value-added carboxylic acids, exemplified in reaction 1:
converting CO2 and butadiene (C4H6) into adipic acid (HO2C(CH2)4CO2H;
hexanedioic acid), a Nylon precursor, produced at 2.5 Mt a-1. Reaction (1) alone could
fix ca. 1.5 Mt CO2 a-1.
This process represents the up-conversion of a C4 hydrocarbon to a C6 hydrocarbon
(i.e. a 33% decrease in carbon required from petrochemical sources). However, as the
butadiene (C4H6) precursor can be produced industrially from ethanol, the use of biosourced ethanol would obviate the need for any non-renewable hydrocarbon source.
The CO2 reduction reaction will be coupled with the oxidation of water to oxygen or
the oxidation of hydrogen in an electrochemical reactor, which could be powered by
solar energy using photovoltaics.
One of the project’s scientific challenges is the development of electro-catalysts to
decrease the overpotentials and hence specific electrical energy requirements for the
reduction of solvent-absorbed CO2, the choice of solvent being the first decision. As
a second hydrogenation step is required in reaction 1, the two reactions could also be
combined, utilising hydrogen from proton/water reduction which occurs in parallel with
CO2 reduction. The expertise and knowledge of the PI in catalyst development will be
deployed with those of the Co-I’s in electro-catalysis (AK) and electrochemical
engineering (GK). Recent publications on homogeneous (pyridine-based) catalysts for
CO2 reduction alone are contradictory but worthy of further study with possible novel
application to reaction (1).2 The engineering challenges lie in the product separation
and the reactor design, especially for the reduction reaction (1) requiring a novel,
judiciously designed ‘gas diffusion cathode’, as used in fuel cells, but in this case to
facilitate contacting of CO2 and alkene (gas), electrons (electronically conducting
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet
Science and Solutions for a Changing Planet
cathode ± catalyst) and electrolyte solution. Recent publications3 on the
electrochemical reduction of CO2 alone will provide a starting point for this project.
References
1. Kondratenko, E. V.; Mul, G.; Baltrusaitis, J.; Larrazábal, G. O.; Pérez-Ramírez, J.,
Status and perspectives of CO2 conversion into fuels and chemicals by catalytic,
photocatalytic and electrocatalytic processes, Energy Environ Sci. 2013, 6, 3112.
2. C-H. Li, G-Q. Yuan, X.-C Ji, X-J. Wang, J-S. Ye, H-F. Jiang, Highly regioselective
electrochemical synthesis of dioic acids from dienes and carbon dioxide,
Electrochimica Acta 2011, 56, 1529–1534.
3. P. Bumroongsakulsawat, G.H. Kelsall, Tinned graphite felt cathodes for scale-up of
electrochemical reduction of aqueous CO2, Electrochimica Acta 2015, 159, 242–251.
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet