A NiO _x ‐Mediated Z‐Scheme Hybrid Photocatalyst for Efficient and Selective Oxidation of Inert C(sp ³ )–H Bonds

ABSTRACT The selective photocatalytic oxidation of inert benzylic C(sp 3 )–H bonds to aromatic aldehydes using molecular oxygen remains a formidable challenge due to uncontrolled overoxidation and poor charge utilization. Herein, we report a NiO x ‐mediated Z‐scheme NiOx‐BWO‐TiO 2 hybrid photocatalyst that overcomes these limitations to achieve a benzaldehyde production rate of 2880 µmol g − 1 h − 1 with 91% selectivity, which is 6.0 and 4.7 times higher than pristine TiO 2 and BWO respectively, by using O 2 as a green oxidant. The amorphous NiO x interlayer functions as a solid‐state charge mediator, enabling recombination of low‐energy carriers while preserving high‐potential holes in BWO for C‐H activation and strongly reducing electrons in TiO 2 for selective O 2 reduction to superoxide. Isotopic 1 8 O 2 labeling confirms molecular oxygen as the exclusive carbonyl source, and mechanistic validation through XPS, EPR spectroscopy, and radical trapping experiments establishes NiO x as a dynamic hole reservoir and •O 2 − as the terminal oxidant. The catalyst exhibits robust stability over five cycles and broad substrate scope, establishing a green and sustainable platform for selective C‐H functionalization under mild and energy‐efficient conditions.