Stabilizing Cu Catalysts for Electrochemical CO2 Reduction Using a Carbon Overlayer

Significant efforts have been devoted to the investigation of catalysts for converting CO2 into C2+ products. Cu catalysts are attractive for their initial selectivities but limited by the low stability over time. Herein we investigated the stability of Cu catalysts in an operating CO2RR environment. Hydroxides in electrolytes were found to play a key role in morphology evolution of Cu catalysts and thus result in decreasing Faradaic efficiencies of C2+ products. To this end, we deposited a porous carbon overlay on Cu catalysts through a thermal annealing method. Physical characterizations and electrochemical measurements showed that the morphology of Cu catalysts and Faradaic efficiencies of products were well maintained during the reaction. As evidenced by Fourier transform infrared spectroscopy with phenolphthalein as a probe, the added carbon overlay could effectively resist the influence of hydroxide corrosion on Cu catalysts. This study provides an efficient strategy to improve the stability of copper catalysts toward electrochemical CO2 reduction.