Modulating oxygen vacancies to simultaneously promote Pd atom stability and O activation over Pd/CeO2 catalysts for enhancing catalytic efficiency and durability

Abstract

Developing a synthetic strategy for stabilizing single-atom catalysts is crucial for improving atom utilization and achieving the ultimate catalytic efficiency. Herein, a thermal shock strategy was utilized to fabricate thermally stable Pd-based single-atom catalysts with excellent catalytic activity. Results revealed that the calcination method governed the formation of oxygen vacancies, resulting in vast differences in the dispersity, stability and reactivity of Pd species. The thermal shock method (PdCe-TS) facilitated the generation of oxygen vacancies to activate and stabilize Pd via strong metal–support interaction. By contrast, the conventional calcination method (with a slow heating rate, PdCe-NC) suppressed the formation of oxygen vacancies, driving the formation of Pd clusters from Pd atoms. The coexistence of atomically dispersed Pd²⁺ and sufficient oxygen vacancies dramatically facilitates the activation of O₂ and CO via abundant electronic transmission at the interface, and the facile removal of CO₂ further accelerates the overall reaction. Consequently, compared with the PdCe-NC catalysts, the PdCe-TS catalysts exhibited lower apparent activation energy and a higher CO oxidation reaction rate, demonstrating enhanced catalytic performance and durability.