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

The electrocatalytic CO₂ 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 C₂₊ 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 C₂₊ 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 H₂ evolution.