Abstract

Electrochemical carbon dioxide (CO2) conversion to hydrocarbon fuels, such as methane (CH4), offers a promising solution for the long-term and large-scale storage of renewable electricity. To enable this technology, CO2-to-CH4 conversion must achieve high selectivity and energy efficiency at high currents. Here, we report an electrochemical conversion system that features proton-bicarbonate-CO2 mass transport management coupled with an in-situ copper (Cu) activation strategy to achieve high CH4 selectivity at high currents. We find that open matrix Cu electrodes sustain sufficient local CO2 concentration by combining both dissolved CO2 and in-situ generated CO2 from the bicarbonate. In-situ Cu activation through alternating current operation renders and maintains the catalyst highly selective towards CH4. The combination of these strategies leads to CH4 Faradaic efficiencies of over 70% in a wide current density range (100 – 750 mA cm-2) that is stable for at least 12 h at a current density of 500 mA cm-2. The system also delivers a CH4 concentration of 23.5% in the gas product stream.

Electrochemical CO2 conversion to methane offers a promising solution for the large-scale storage of renewable electricity, yet the catalytic selectivity at high current density still needs to be refined. Here the authors report to use both dissolved CO2 and in-situ generated CO2 from bicarbonate to sustain high local CO2 concentration around Cu electrode and thus achieve selective CO2 conversion to methane.

Details

Title
High-rate and selective conversion of CO2 from aqueous solutions to hydrocarbons
Author
Obasanjo, Cornelius A. 1 ; Gao, Guorui 1 ; Crane, Jackson 1   VIAFID ORCID Logo  ; Golovanova, Viktoria 2 ; García de Arquer, F. Pelayo 2   VIAFID ORCID Logo  ; Dinh, Cao-Thang 1   VIAFID ORCID Logo 

 Queen’s University, Department of Chemical Engineering, Kingston, Canada (GRID:grid.410356.5) (ISNI:0000 0004 1936 8331) 
 The Barcelona Institute of Science and Technology, ICFO–Institut de Ciències Fotòniques, Barcelona, Spain (GRID:grid.473715.3) (ISNI:0000 0004 6475 7299) 
Pages
3176
Publication year
2023
Publication date
2023
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2821503140
Copyright
© The Author(s) 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.