Synergistic BiC bond bridges and Bi vacancies orchestrate accelerated charge transfer in S-scheme heterojunctions for photocatalytic H2 production and pollutant degradation

Precise engineering of interfacial electron transfer is pivotal for advancing photocatalytic performance. Herein, a metallic Bi-bridged, Bi-vacancy-rich Bi@Bi V -Bi 2 O 3 /CN S-scheme heterojunction featuring orchestrated interfacial charge transport is designed. Bi vacancies in Bi 2 O 3 acts as an efficient hole extraction agent, driving the directional migration of photogenerated holes, while the in-situ generated metallic Bi establishes a rapid electron transfer channel via Bi C interfacial bonding to concentrate electrons onto the CN substrate. Notably, the p-orbital hybridization of Bi with the p orbitals of C modulates the local electronic structure, synergistically enhancing interfacial electron dynamics. X-ray absorption spectroscopy confirms the formation of Bi C with strong electronic coupling, while density functional theory (DFT) calculations reveal directed charge migration at the Bi@Bi V -Bi 2 O 3 and CN interfaces. This dual-channel synergistic mechanism achieves highly efficient spatial separation of charge carriers while preserving highly reductive electrons and highly oxidative holes, providing an ideal platform for photocatalytic hydrogen evolution and organic pollutant degradation. Benefiting from the engineered interfacial pathways, Bi@Bi V -Bi 2 O 3 /CN achieves superior photocatalytic degradation of antibiotic, with a tetracycline (TC) degradation rate constant (0.019 min −1 ) and a hydrogen production rate (2903.30 μmol g −1  h −1 ) reaching 5.8 and 12.1 times that of pristine CN, respectively. This work provides novel insights and a theoretical foundation for designing efficient S-scheme photocatalysts with dual-functional capabilities for pollutant degradation and clean energy production.