Promotion Effect of Well-Defined Deposited Water Layer on Carbon Monoxide Oxidation Catalyzed by Single-Atom Alloys.

Single-atom alloys (SAAs) exhibit excellent catalytic performance and unique electronic structures, emerging as promising catalysts for potential industrial reactions. While most of them have been widely employed under reducing conditions, few are applied in oxidation reactions. Herein, using density functional theory calculations and microkinetic simulations, we demonstrate that a well-defined one water layer can improve CO oxidation on model SAAs, with reaction rates increased by orders of magnitude. It is found that the formation of hydrogen bonds and the transfer of charges effectively enhance the adsorption and activation of oxygen molecules at the H 2 O/SAA interfaces, which not only increases the surface coverage of O 2 species but also reduces the energy barrier of CO oxidation. The proposed strategy in this work would extend the application range of SAA catalysts to oxidation reactions.