Constructing a Stable Single-Atom Pt Catalyst on CeO2 Nano-Islands To Enhance Water Resistance and Catalysis Performance via H2O Activation.

Single-atom catalysts are prone to migration and aggregation in the presence of water, leading to a decrease in catalyst activity. How to transform the action of water from an inhibitor to a promoter is a major challenge faced by Pt single-atom catalysts. In this study, a distinctive single-atom nano-islands catalyst (Pt1@CeOx/SiO2) was designed to investigate the effect of introducing nano-islands on the catalytic and water-resistant performance of Pt single-atom catalysts. It was found that platinum single atoms were confined on CeOx nanoclusters, effectively suppressing their migration and aggregation during the reaction. Notably, the Pt1@CeOx/SiO2 catalyst exhibited significant low-temperature activity, thermal stability, and water resistance. Compared with the other catalysts, the strong interaction between Pt and CeOx nano-islands over the Pt1@CeOx/SiO2 catalyst not only stabilized the Pt single atoms but also promoted the generation of abundant active species (Ptδ+ and Ce3+ species), active oxygen species, and weak acid sites during the reaction, thereby exhibiting a "dynamic optimization" phenomenon. More importantly, in humid conditions, the nano-islands effectively reduce the adsorption capacity for H2O while facilitating the activation of H2O and O2, leading to the generation of more active oxygen species (*O, *OH, and *OOH). This work clarifies the mechanism of nano-islands on catalytic performance, providing a well-defined insight for designing efficient, stable, and water-resistant noble metal based single-atom catalysts.