Reduced Graphene Oxide Overlayer on Copper Nanocube Electrodes Steers the Selectivity Towards Ethanol in Electrochemical Reduction of Carbon Dioxide

Developing copper-based electrocatalysts that favor high-value multi-carbon oxygenates is desired, given their use as platform chemicals and as a direct fuel for transportation. Combining a CO-selective catalyst with copper shifts the selectivity of CO₂ electroreduction toward C₂ products. Herein, we developed a reduced graphene oxide (rGO)-modified copper nanocube electrocatalyst that could shift the selectivity of CO₂ electroreduction towards ethanol (Faradaic efficiency 76. 84 % at −0.9 V vs. reversible hydrogen electrode (RHE)). Spectroelectrochemical Raman analysis reveals a higher population of *C₂H_xO_y intermediates at −0.9 V vs. RHE on the rGO-modified copper nanocube electrocatalyst surface, which coincides with the highest faradaic efficiency of ethanol upon CO₂ electroreduction at the same potential. Our results demonstrate that the rGO modification can enhance ethanol selectivity through a probable tandem electrocatalysis mechanism and provide insights into controlling electrocatalytic activity and product selectivity in the CO₂ electroreduction reaction.