Facile electrochemical fabrication of Ag/Cu bi-metallic catalysts and the dependence of their selectivity for electrochemical CO2 reduction on the surface composition

Abstract Herein, bimetallic Ag/Cu nanowires (NWs) are prepared by electrochemical synthesis of Cu NWs and subsequent Ag galvanic displacement for the electrochemical reduction of CO2 to CO. The delicate execution of the displacement fabricates bimetallic NWs that possess controlled surface composition. The surface composition of NW is precisely controlled by varying the displacement time, and it is revealed by numerical and experimental methods that the catalytic activity is closely affected by the composition. The surface coverage of Ag measured based on under potential deposition according to the displacement time ranges from 70% to 94.3%. An increase in the Ag surface composition results in an improvement in the CO Faradaic efficiency from 29.8% to 39.6% and a significant increase in CO partial current density compared with Cu NWs and Ag foil. Namely, the catalytic activity of Ag/Cu NWs is dependent on the Ag coverage, and is governed by scaling relation.