No abstract

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 CO 2 electroreduction toward C 2 products. Herein, we developed a reduced graphene oxide (rGO)-modified copper nanocube electrocatalyst that could shift the selectivity of CO 2 electroreduction towards ethanol (Faradaic efficiency 76. 84 % at À 0.9 V vs. reversible hydrogen electrode (RHE)). Spectroelec-trochemical Raman analysis reveals a higher population of *C 2 H x O y intermediates at À 0.9 V vs. RHE on the rGO-modified copper nanocube electrocatalyst surface, which coincides with the highest faradaic efficiency of ethanol upon CO 2 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 CO 2 electroreduction reaction.