Copper-indium hydroxides derived electrocatalysts with tunable compositions for electrochemical CO2 reduction

Abstract Bimetallic Cu-In hybrid electrocatalysts are promising noble metal-free catalysts for selective electrochemical CO2 reduction reaction (ECO2RR). Most reports show Cu-In catalysts are selective towards CO evolution. However, few show similarly high selectivity towards formate. Herein we fabricated composition tunable Cu-In hydroxides (CuxIny-OH) by the hydrothermal method and studied their composition effect on electrochemical CO2 reduction in detail. We found that the selectivity of CO2 reduction products shifted from CO to formate when the content of In increased in the CuxIny-OH electrocatalysts. The Cu rich electrocatalyst mostly produced CO, which could achieve a Faradaic efficiency (FE) to 75.8% at −0.59 V vs. RHE (Cu76In24 based electrocatalysts). In comparison, the In rich electrocatalysts selectively produced formate, which possessed the FE of formate up to 85% at −1.01 V vs. RHE. Our work systematically illustrates the composition effect on hybrid catalysts, and provides insights into the design of highly selective catalysts for ECO2RR.