Copper-catalysed carbon monoxide electrolysis under dynamic operation

Abstract

Electrochemical reduction of carbon monoxide (CO) into valuable multicarbon products offers a promising pathway for carbon utilization. However, most CO electrolysers are developed for steady-state operation, whereas integration with intermittent renewable electricity may pose technical challenges. Here we show that repeated cycling between power-on and power-off modes rapidly degrades copper(Cu)-based cathodes, either through carbonate accumulation under CO-rich conditions or oxidation to Cu2O under Ar environments. To circumvent these Cu degradation issues, we introduce a controlled power-down strategy where the Cu cathode is kept at a slightly more negative potential than open-circuit potential, effectively preventing carbonate formation and Cu oxidation. This strategy enables stable dynamic operation of a CO electrolyser for more than 750 h without any significant performance loss. Techno-economic analysis indicates that dynamic operation can lower the acetic acid production cost by up to 26%, leveraging periods of lower electricity prices and thus improving viability for integrating with intermittent renewable electricity.

Group Members

William A. Goddard III

Charles and Mary Ferkel Professor of Chemistry, Materials Science, and Applied Physics; Director, Materials and Process Simulation Center, Caltech