Reactant-Induced Dynamic Stabilization of Highly Dispersed Pt Catalysts on Ceria Dictating the Reactivity of CO Oxidation

The reactant-induced dynamics of catalysts under harsh conditions have a profound impact on their reactivity and stability, and identification of the underlying principle and active sites is vital for the rational design of catalysts. Based on a comprehensive first-principles investigation, we reveal here a reactant-induced dynamic stabilization of the highly dispersed Pt complexes that formed on ceria surfaces and their decisive role in CO oxidation. Compared to those of Pt nanoparticles, reactant-stabilized single-nuclear Pt 1 (CO) m and/or multinuclear Pt 8 (CO) n complexes prevail under CO-rich conditions on the defective CeO 2 (111), (110), and (100) surfaces considered. At lower temperatures, the Pt 1 (CO) complexes emerge as active sites for CO oxidation, whereas at higher temperatures, the active sites transit dynamically to the Pt 8 (CO) 9 complexes. We found that oxygen defects not only stabilize the complexes but also promote activity via the facile Mars–van Krevelen mechanism. These insights reveal the great impact of the reactant-interference structure–activity relationship under operando conditions.