Sintering resistance of Pd single atoms on steam-modified ceria: deciphering the role of hydroxyl groups

Abstract

It remains a significant challenge to achieve good stability for single-atom catalysts while maintaining high activity. On the basis of observing the sintering resistance up to 800 °C of Pd single atoms dispersed on OH-modified CeO₂ and their sustainable activity for CO oxidation at low temperature, the relationship between the unique structure and catalytic performance of the single-atom catalyst was deeply investigated. The structural characterization revealed that the OH groups on the ceria can anchor the Pd-loaded sites and promote the formation of a stable OH-Pd₁O₄-doped structure, leading to its high-temperature stability. Moreover, low-temperature activity retention was attributed to the multiple active palladium species (Pd²⁺, Pd^δ+, and Pd⁰). This study highlights the crucial role of structural regulation in determining catalyst performance, and provides guidance for the rational design of high-performance single-atom catalysts.