Partially reduced PdOx nanoparticles strongly interacting with defect-rich ceria via dynamic redox pulse for complete methane oxidation

Tuning the surface structures of active metal species to desired states is a rational approach to achieve high performance in heterogeneous catalysis. However, modulating the coordination environments and electronic states while maintaining a consistent nanoparticle size remains challenging. This difficulty has led to controversial findings regarding the optimal surface structures of supported palladium nanoparticles for complete methane (CH 4 ) oxidation. In addition, palladium catalysts are vulnerable to deactivation during reactions due to inadequate anchoring effects on support materials. Herein, we engineer the PdO x nanoparticles with low oxygen coordination and a partially reduced Pd δ+ (0 < δ < 2) state via a dynamic redox pulse method. During this process, oxygen vacancy defects on ceria are simultaneously enriched, thereby establishing strong interaction that immobilizes the PdO x nanoparticles. The PdO x catalyst exhibits superior activity for CH 4 oxidation under wet conditions, outperforming other ceria-supported palladium nanoparticles. Furthermore, the reinforced interaction endows remarkable structural robustness, preventing deactivation under harsh reaction conditions. Theoretical simulations elucidate the redox-driven transformation and stabilization of palladium species, establishing a direct structure-activity relationship among distinct palladium motifs for CH 4 activation. The PdO x catalyst demonstrates consistent performance in bench-scale reactions, offering valuable design strategies for optimally nanostructured palladium catalysts for complete CH 4 oxidation. • Electronic structures of palladium nanoparticles on ceria are precisely controlled. • Partially reduced PdO x with Pd δ+ (0 < δ < 2) is engineered via dynamic redox pulse. • Alternating redox atmosphere generates abundant oxygen vacancy defects on ceria. • Optimal PdO x nanoparticles exhibit superior activity for complete methane oxidation. • Strong interaction of PdO x -ceria endows robust structure, enabling high durability.