Sustainable Formate Synthesis: Integrating Ethylene Glycol Oxidation with Carbon Dioxide Electrocatalysis Using Redox-Stabilized Earth-Abundant Electrodes
Ifra Bashir, James McGettrick, Moritz F. Kühnel, Bilal Sarfraz, S. Arshad, Ali Rauf
Abstract
Carbon dioxide electroreduction (CO 2 ER) coupled with water oxidation (oxygen evolution reaction, OER) presents a promising solution for effectively mitigating global warming. However, this process is compromised by the sluggish OER, which yields only undesirable O 2 . Here, we couple selective CO 2 ER with partial ethylene glycol oxidation (EGO) to concurrently produce formate in both half-reactions. The enhancement of active sites and optimization of formate selectivity are the principal objectives during the design of both electrodes. For CO 2 ER, redox stabilization of Sn-based cathodes is investigated via Pb doping, thus ultimately improving the Faradaic efficiency from 68% to ∼89%. To replace OER with EGO, we employed CuO@Ni(OH) 2 on copper foam, reducing the applied potential by 200 mV at 50 mA/cm 2 . Finally, an EGO-coupled CO 2 electrolyzer achieves 10 mA/cm 2 at an overall cell voltage 180 mV lower than that of a conventional CO 2 electrolyzer. This study showcases the integration of divergent electrochemical processes for concurrent electrosynthesis without precious metals to achieve cost-effective and sustainable formate production from CO 2 and plastic waste.