Cu3V2O8/BiVO4 S-Scheme Heterojunction for Visible-Light Pollutant Degradation and Hydrogen Evolution

A Cu3V2O8 (CVO)/BiVO4 S-scheme heterojunction was constructed via a facile hydrothermal strategy to achieve efficient visible-light-driven pollutant degradation and hydrogen evolution. Structural characterization confirmed the formation of an intimate heterointerface, while DFT calculations revealed electron migration from Cu3V2O8 to BiVO4 and the establishment of an internal electric field. UPS measurements further supported the predicted interfacial electronic alignment, with experimentally determined work functions of 5.18 eV for BiVO4 and 4.60 eV for Cu3V2O8, consistent with electron redistribution from CVO toward BiVO4 upon heterojunction formation. The optimized 15 wt % CVO/BiVO4 photocatalyst exhibited the highest activity, delivering apparent rate constants for penicillin G and 4-chlorophenol degradation that were 4.5 and 3.5 times higher, respectively, than those of pristine BiVO4, together with a hydrogen evolution rate of 3157.67 μmol g–1 h–1 under visible-light irradiation. Photoelectrochemical studies, Mott–Schottky analysis, reactive-species trapping, UPS, and DFT calculations collectively supported the proposed S-scheme charge-transfer pathway responsible for the enhanced photocatalytic performance