LAUSR

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 N3C 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 H2O2 assisted advance oxidation technology. This work brings a new sight on the coordinated atoms dominant oxidation process.