Stable and Active Oxidation Catalysis by Cooperative Lattice Oxygen Redox on SmMnO Mullite Surface.

The correlation between lattice oxygen (O) binding energy and O oxidation activity imposes a fundamental limit in developing oxide catalysts, simultaneously meeting the stringent thermal stability and catalytic activity standards for complete oxidation reactions under harsh conditions. Typically, strong O binding indicates a stable surface structure, but low O oxidation activity, and . Using nitric oxide (NO) catalytic oxidation as a model reaction, we demonstrate that this conflicting correlation can be avoided by cooperative lattice oxygen redox on SmMnO mullite oxides, leading to stable and active oxide surface structures. The strongly bound neighboring lattice oxygen pair cooperates in NO oxidation to form bridging nitrate (NO) intermediates, which can facilely transform into monodentate NO by a concerted rotation with simultaneous O adsorption onto the resulting oxygen vacancy. Subsequently, monodentate NO species decompose to NO to restore one of the lattice oxygen atoms that act as a reversible redox center, and the vacancy can easily activate O to replenish the consumed one. This discovery not only provides insights into the cooperative reaction mechanism but also aids the design of oxidation catalysts with the strong O binding region, offering strong activation of O, high O activity, and high thermal stability in harsh conditions.