Invited Speech

Electrochemical conversion of CO₂ to useful chemicals (e.g. CO) is of great significance to the reuse of CO₂ as carbon source, whereas the production yield in aqueous system is not high enough to meet the requirement of industrial application. In this paper, electrochemical reduction of CO₂ in aqueous 0.5 M KHCO₃ solution was studied by the use of novel porous silver electrode, which was fabricated on silver plate by a potentiodynamic dealloying in NaCl solution with annealed Ag-Zn sample as precursor. Analysis of gaseous products revealed that the porous silver exhibited superior catalytic performance for the reduction of CO₂ to CO than that on Ag plate. Interestingly, the surface of as-synthesized porous silver was not pure silver, but consisted of silver and zinc alloy. The faradic efficiency of CO was affected greatly by the zinc content in the porous silver. Moreover, the activity of the porous silver electrode was stable over cycles of several hours. By changing nanostructure and/or alloy composition, new paths to further improved catalysts are expected.