Optimising the electrochemical reduction of CO2 to oxalic acid in propylene carbonate

Sale, H., Ubbara, G. R. and Symes, M. D. (2023) Optimising the electrochemical reduction of CO2 to oxalic acid in propylene carbonate. Sustainable Energy and Fuels, (doi: 10.1039/D3SE00652B)

Abstract

Carbon dioxide (captured from the atmosphere or obtained by other routes) constitutes a useful and widely-available building block for producing numerous valuable chemicals and fuels. Electrochemical methods for carbon dioxide reduction offer advantages in terms of scalability, the prospect of coupling directly to renewable power sources and the ability to reduce carbon dioxide without the co-production of harmful by-products. Of the various possible products of carbon dioxide electroreduction, oxalate/oxalic acid is an especially attractive target on account of its wide use in a number of chemical and pharmaceutical processes. Herein, we report the results of a study on carbon dioxide electroreduction to oxalate/oxalic acid in a propylene carbonate solvent system, catalysed by the addition of benzonitrile. Our results show that the use of benzonitrile as a homogeneous electrocatalyst improves the Faradaic and reaction yields of oxalate/oxalic acid production, as well as the area-normalised rate of formation of oxalate/oxalic acid, giving a new record rate of formation of 1.65 ± 0.35 mM cm−2 h−1 (averaged over 1 h) at a voltage of ‒2.7 V vs SCE (‒2.46 V vs SHE). Such metrics in turn suggest that the electrochemical reduction of carbon dioxide to C2+ products via oxalate could be a promising avenue for further development for the sustainable production of key chemical feedstocks.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sale, Halilu and Symes, Professor Mark and Ubbara, Mr Gangi Reddy
• Authors: Sale, H., Ubbara, G. R., and Symes, M. D.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Sustainable Energy and Fuels
• Publisher: Royal Society of Chemistry
• ISSN: 2398-4902
• ISSN (Online): 2398-4902
• Published Online: 06 September 2023
• Copyright Holders: Copyright © 2023 The Royal Society of Chemistry
• First Published: First published in Sustainable Energy and Fuels 2023
• Publisher Policy: Reproduced under a Creative Commons License
• Data DOI: 10.5525/gla.researchdata.1497

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
316623		Decoupled Electrolysis for the Production of Zero-Carbon Hydrogen	Mark Symes	Engineering and Physical Sciences Research Council (EPSRC)	EP/W033135/1	Chemistry
312636		Driving energetically uphill processes using metal-ligand coordination complexes - Renewal	Mark Symes	The Royal Society (ROYSOC)	URF\R\211007	Chemistry