WS ₂ Nanoflake/Phosphorus-Doped Graphitic Carbon Nitride Nanosheet Composite S-Scheme Photocatalyst for Simultaneous H ₂ O ₂ Generation and Methyl Violet Degradation

An effective photocatalyst was developed for simultaneous hydrogen peroxide (H2O2) generation and degradation of pollutants, offering a promising strategy to deal with both the energy crisis and environmental pollution based on WS2/ phosphorus-doped g-C3N4 (WPCN). The 2.5WPCN, 5WPCN, and 7.5WPCN nanomaterials were synthesized through a combination of wet impregnation and calcination techniques. The strong attachment of WS2 nanoflakes onto the nanosheets of PCN facilitates effective segregation of photoproduced excitons with outstanding redox properties, attributed to the formation of an S-scheme heterojunction between WS2 nanoflakes and PCN nanosheets through W–N bonding verified from XPS measurement. The W–N bond at the interfacial region behaves as a bridge for enhanced charge separation pathways. Among the series, the optimized 5WPCN heterojunction achieved an H2O2 production rate of 1426.71 μmol g–1 h–1 paired with simultaneous degradation of 93% of methyl violet (MV), wherein the MV molecules functioned as a hole quencher during photocatalytic activity. The enhanced photocatalytic performance was figured out by high cathodic current density and heightened separation of charge carriers supported by PL, EIS, and transient photocurrents measurement. The S-scheme charge transfer pathway was verified from radical quenching experiments, and the work function was estimated from UPS analysis assisted by ESR and TRPL analysis. This work provides a unique idea for designing an S-scheme photocatalyst for heightened H2O2 generations with simultaneous contaminant degradation.