Benchmarking the Electrochemical CO₂ Reduction on Polycrystalline Copper Foils: The Importance of Microstructure Versus Applied Potential

Abstract

Abstract Copper is one of the most promising catalysts for the CO 2 reduction reaction (CO 2 RR) due to its unique capability of producing multicarbon products in appreciable quantities. Most of the CO 2 RR research efforts have been directed towards the development of new electrocatalysts to either increase product selectivities or decrease overpotentials. In contrast, only a few studies have systematically tested or benchmarked CO 2 RR performances of electrocatalysts. In this paper, for the first time, the performances of five different polycrystalline copper foils purchased from different suppliers are benchmarked for their CO 2 RR performance. Their differences are characterized in terms of microstructural features and the effect that these microstructural properties have on the electrocatalytic behavior during potentiostatic CO 2 RR experiments are evaluated. It is shown that the potential applied is the dominant factor controlling CO 2 RR selectivities, leading to the conclusion that microstructural properties of polycrystalline copper electrodes have a negligible effect on the outcome of CO 2 RR experiments.