Ag Displacement on Cu Foam with Additives for Electrochemical Reduction of Carbon Dioxide to Carbon Monoxide

For electrochemical reduction of carbon dioxide to carbon monoxide, an Ag catalyst supported by Cu foam was prepared electrochemically by bubble‐templated Cu electrodeposition and subsequent Ag galvanic displacement. The morphology and crystal structure of the displaced Ag on the Cu foam varied significantly depending on the type of additive. Electrochemical analysis revealed variations in the electrochemical surface area and different Ag and Cu surface compositions depending on the type of additive used in the Ag galvanic displacement step. Among the prepared Ag/Cu foams, the foam having the highest Ag(220)/Ag(111) ratio exhibited the highest CO Faradaic efficiency at a certain constant potential. In the potential range between −0.46 and −0.96 V RHE , the Ag(220)/Ag(111) ratio significantly affected the normalized CO partial current, showing the importance of control of a certain facet in the Ag crystal structure by the additives.