Engineering the interfacial electron interaction of Co3O4/CeO2 heterostructure for robust CO-SCR in oxygen-rich conditions

Co 3 O 4 /CeO 2 catalyst with rich oxygen vacancies was fabricated. • Co 3 O 4 /CeO 2 catalyst achieves 100% NO x conversion within 225 −400 °C under oxygen-enriched conditions. • The heterostructure interface induces a strong Ce(4 f)–O(2p)–Co(3d) orbital coupling and triggers electron redistribution. • The heterostructure and oxygen vacancies ensured the pathway less affected by O 2 . The development of efficient and low-cost catalysts for the selective catalytic reduction of NO by CO (CO-SCR) under aerobic conditions remains a critical challenge. Heterostructure catalysts, particularly those engineered at the interface between rare earth and transition metal oxides, represent a promising frontier for the CO-SCR reaction. However, a deep understanding of their catalytic mechanism and active sites remains limited. In this work, the Co 3 O 4 /CeO 2 heterostructure catalyst with dispersed Co 3 O 4 nanoparticles on CeO 2 is designed and synthesized via a two-step precipitation method, serving as a model system. The optimized catalyst exhibits superior performance with 100% NO conversion across a wide temperature window (225–400 °C) and robust thermal stability, outperforming pure CeO 2 . Advanced spectral characterization and density functional theory calculations reveal that the heterostructure interface induces a strong Ce(4 f)-O(2p)-Co(3d) orbital coupling, which triggers electron redistribution. This unique interface environment optimizes the adsorption and activation of NO molecules and lowers the N-O bond cleavage energy, thereby enabling the high catalytic performance. This work offers a facile synthesis strategy for designing high-performance heterostructure catalysts and provides fundamental insight into the interface-driven mechanism for CO-SCR applications. Download: Download high-res image (215KB) Download: Download full-size image