Effect of mass transfer and kinetics in ordered Cu-mesostructures for electrochemical CO2 reduction

Abstract Mass transfer, kinetics, and mechanism of electrochemical CO 2 reduction have been explored on a model mesostructure of highly-ordered copper inverse opal (Cu-IO), which was fabricated by Cu electrodeposition in a hexagonally-closed packed polystyrene template. As the number of Cu-IO layers increases, the formation of C 2 products such as C 2 H 4 and C 2 H 5 OH was significantly enhanced at reduced overpotentials (∼200 mV) compared to a planar Cu electrode. At the thickest layer, we observe for the first time the formation of acetylene (C 2 H 2 ), which can be generated through a kinetically slow reaction pathway and be a key descriptor in the unveiling of the C C coupling reaction mechanism. Based on our experimental observation, a plausible reaction pathway in Cu mesostructures is rationalized.