Electrodeposited Cu2O Films on Gas Diffusion Layers for Selective CO2 Electroreduction to Ethylene in an Alkaline Flow Electrolyzer

Abstract

AbstractNovel electrodes for the electroreduction of CO2 were prepared by the electrodeposition of copper (I) oxide (Cu2O) catalytic films on a gas diffusion layer. Different electrodes were prepared by varying the deposition time, corresponding to catalyst loadings of 0.37, 0.74, 2.22, 3.70 mg cm−2 and a total charge density of 0.5, 1, 3, and 5 C cm−2, respectively. The electrodes were characterized with SEM, XRD, and UPD. The effect of catalyst loading on the selectivity towards ethylene was investigated in an alkaline flow electrolyzer under ambient conditions. The electrodes were found to be highly selective (>60 %) towards ethylene. The 1 C cm−2 electrode reached Faradaic efficiency values as high as 67 % at industrially relevant current densities of 183 mA cm−2, −0.8 V cathode overpotential and 36 % cell energy efficiency. This performance was attributed to the interplaying role of applied potential, local pH, availability of active sites, and reduced CO2 mass transport limitations.