Photocatalytic　oxidation　of　nitrogen　oxide　(NO)　through　molecular　oxygen　activation　offers　an　appealing　solution　for　addressing　air　environmental　crisis.　However,　the　low　activity　and　selectivity　of　the　oxygen　reduction　reaction,　as　well　as　the　NO2　emission　from　the　photolysis　of　monodentate　NO3–,　severely　restrict　the　NO　photooxidation　efficiency.　Herein,　a　photocatalyst　tailored　for　NO　oxidation　is　prepared　by　depositing　gold　(Au)　nanoparticles　onto　a　crystalline　carbon　nitride　(CCN)　support　by　a　facile　wet-chemical　reduction　method.　In-situ　and　quasi　in-situ　characterizations　demonstrate　that　the　Au　active　sites　could　facilitate　the　one-electron　activation　of　oxygen,　forming　superoxide　radical　intermediates.　The　adsorption　configuration　of　NO3–　products　transitions　from　a　weak　monodentate　binding　mode　to　a　stronger　bidentate　mode　to　mitigate　the　risk　of　unfavorable　photolysis.　As　a　result,　an　apparent　NO　removal　ratio　of　92.8　%　within　the　first　5　min　of　irradiation　at　400　nm　wavelength　light　is　achieved　over　the　as-synthesized　Au/CCN　photocatalyst.　The　decay　rate　of　k1　over　Au/CCN　(–0.001　min−1)　surpasses　the　CCN　(–0.008　min−1)　within　150　min　irradiation　of　the　light,　indicating　higher　stability　and　efficiency　of　the　Au/CCN　photocatalyst　than　that　of　CCN.　This　strategy　shows　the　importance　of　the　rational　design　of　the　active　sites　to　enhance　molecule　oxygen　activation　and　reaction　intermediates　production　to　solve　air　pollution　remediation　due　to　NOx.　©　2025