Oxygen/Nitrogen Dual‐Vacancy‐Engineered Bi ₂ MoO ₆ /g‐C ₃ N ₄ S‐scheme Heterojunction Nanosheets for Visible‐Light‐Driven Photosynthesis of Benzonitriles

ABSTRACT Nitrogen‐containing organic compounds, particularly nitriles, are indispensable building blocks in pharmaceuticals and fine chemicals, yet their conventional synthesis often relies on toxic cyanide sources and energy‐intensive conditions. Herein, we present a visible‐light‐driven (λ = 420 nm) photocatalytic ammoxidation of benzyl alcohol to benzonitrile at room temperature. A rational design of an S‐scheme heterojunction photocatalyst, Bi 2 MoO 6 /g‐C 3 N 4 (BMO/CN), incorporating dual active sites through oxygen vacancies (OVs) and nitrogen vacancies (NVs) via precise defect engineering, achieves exceptional catalytic performance with 94% yield and >99% selectivity. The S‐scheme heterojunction not only preserves high redox potentials for simultaneous benzyl alcohol oxidation and O 2 reduction but also enhances charge carrier separation. Crucially, the dual‐vacancy structure significantly enhances the activation of O 2 and NH 3 , leading to efficient generation of O 2 • − radicals and promoting the condensation of NH 3 with the aldehyde intermediate to form an imine species. Mechanistic studies reveal that the reaction proceeds through an optimized cascade pathway involving alcohol oxidation, aldehyde‐amine condensation, and imine dehydrogenation mediated by collaboratively bromine radicals (Br•) and O 2 • − collaboratively to yield benzonitrile. This work presents a novel heterogeneous photocatalytic system for cyanide‐free nitrile synthesis and provides fundamental insights into activity regulation through precise defect engineering and heterojunction design.