Oxygen Vacancy‐Enhanced S‐Scheme C‐ZnO/B‐g‐C ₃ N ₄ Heterostructure for Efficient Photocatalytic Degradation of Methylene Blue

ABSTRACT Developing porous‐structured organic semiconductor photocatalysts with high charge transfer efficiency is crucial for solar energy utilization, yet remains challenging in pollutant remediation. Herein, an S‐scheme C‐ZnO/B‐g‐C 3 N 4 photocatalyst with oxygen vacancies was fabricated through modified biomass‐derived C doping for methylene blue (MB) degradation. The optimized catalyst achieved 97.8% degradation efficiency within 70 min under visible light. UV‐DRS analysis revealed that C doping narrowed the bandgap and enhanced visible‐light absorption. XPS results confirmed the S‐scheme charge transfer pathway in C‐ZnO/B‐g‐C 3 N 4 . The synergistic effects of C doping and oxygen vacancies significantly improved charge separation and facilitated S‐scheme heterojunction formation. The catalyst exhibited superior photocatalytic performance in alkaline conditions and maintained excellent recyclability. Radical trapping experiments identified the primary reactive species as h + > ·O 2 − > ·OH in descending order of contribution. This work provides a promising strategy for solar‐driven pollutant remediation by combining biomass‐derived carbon modification with S‐scheme heterojunction engineering.