(Invited) Nanostructured Copper and Copper Alloys for CO2 Reduction

Abstract

Electrodeposition of Cu/Ag or Cu/Sn alloy films from plating baths containing 3,5-diamino-1,2,4-triazole (DAT) as an inhibitor exhibit high surface area and high CO2 reduction activities. EXAFS shows that the codeposited alloy films are homogenously mixed. An alloy film containing 6% Ag exhibits the best CO2 reduction activities activity with a Faradaic Efficiency (FE) for C2H4 product formation reaching 60% at -0.7 V vs. RHE, a FE for C2H5OH formation reaching 25% at -0.7 V vs. RHE, among the highest reported for this activity. Raman studies show that the origin of the high activity is the stabilization of a Cu2O overlayer along with stabilization of the CO intermediate by the Ag or Sn incorporated in the alloy with the exact speciation a function of the interplay between the added metal and the Cu surface.