Modulating the Site Density of Mo Single Atoms to Catch Adventitious O Atoms for Efficient H₂ O₂ Oxidation with Light

Coordination environment and site density have great impacts on the catalytic performance for single atoms (SAs). Herein, the site density of Mo-SAs on red polymeric carbon nitrides (RPCN) is modulated via a local carbonization strategy to controllably catch adventitious O atoms from open environment. The addition of melamine derivants with hydrocarbyl chains induces local carbonization during RPCN pyrolysis. These local carbonization regions bring abundant graphitic N_3C to anchor Mo-SAs, and most of Mo-SAs catch the O atoms in air, forming the O₂ -covered Mo-N₃ coordination. The dopants of carbon source with different structures and amounts can modulate the site density of Mo-SAs, therefore controlling the amounts of coordinated O atoms. Furthermore, coordinated O atoms around Mo-SAs construct the catalytic environment with Lewis base and gather photo-generated electrons under light. Such O-covered Mo-SAs endow RPCN materials (Mo-RPCN) with a strong ability for hydrogen abstraction, leading to the 99.51% ratio (28.8 mmol min^-1  g^-1 ) rate for thioanisole conversion with H₂ O₂ assisted advance oxidation technology. This work brings a new sight on the coordinated atoms dominant oxidation process.