Promoting CO Electroreduction to C₂₊ Oxygenates by Distribution of Water Dissociation Sites

The electrocatalytic CO 2 or CO reduction reaction is a complex proton‐coupled electron transfer reaction, in which protons in the electrolyte have a critical effect on the surface adsorbed * H species and the multi‐carbon oxygenate products such as ethanol. However, the coupling of * H and carbon‐containing intermediates into C 2+ oxygenates can be severely hampered by the inappropriate distributions of those species in the catalytic interfaces. In this work, the controlled distribution of highly dispersed CeO x nanoclusters is demonstrated on Cu nanosheets as an efficient CO electroreduction catalyst, with Faradaic efficiencies of ethanol and total oxygenates of 35% and 58%, respectively. The CeO x nanoclusters (2−5 nm) enabled efficient water dissociation and appropriate distribution of adsorbed * H species on the Cu surface with carbon‐containing species, thus facilitating the generation of C 2+ oxygenate products. In contrast, pristine Cu without CeO x tended to form ethylene, while the aggregated CeO x nanoparticles promoted the surface density of * H and subsequent H 2 evolution.