Pulsed Electroreduction of  CO 2 on Copper Electrodes‐ II

The pulsed method newly developed by the present authors was applied to electroreduction of on Cu electrodes. It was found that the optimum cathodic bias for generating and was −2.6 V vs. SCE, and the optimum anodic bias for the generation of was slightly more anodic than that of . Total faradaic efficiency for the generation of and became a maximum at 10°C and reached about 65%. Furthermore, increased with increasing reduction time in strong contrast with the conventional potentiostatic electroreduction in which decreased drastically with the reduction time due to the poisoning effect of the products. It was proposed that some surface intermediate formed by the interaction between and the thin oxide layer on a Cu electrode is finally reduced to or , depending on the anodic reactions taking place during the anodic period.