Flower-like In-TiO2@Bi2MoO6 S-scheme heterojunction for efficient visible-light-driven photocatalytic desulfurization of H2S

S-scheme heterojunction photocatalysts have emerged as a promising strategy to overcome the limitations of conventional systems by enabling efficient charge transfer while preserving strong redox capability. In this study, a novel flower-like In-TiO₂@Bi₂MoO₆ S-scheme heterojunction was developed via a simple hydrothermal synthesis for visible-light-driven photocatalytic desulfurization of H₂S. The optimized In-TiO₂-0.4@Bi₂MoO₆ composition (molar ratio of In-TiO₂ to Bi₂MoO₆ = 0.4) achieved complete H₂S removal within 120 min under visible-light irradiation, exhibiting outstanding activity, operational stability, and adaptability to various desulfurization conditions. Mechanistic investigations using VB-XPS, UPS, ESR, DRIFTS and DFT calculations confirmed that the S-scheme configuration accelerated photoinduced charge separation, reduced electron migration distances, and maintained a high redox potential, thereby promoting efficient generation of reactive oxygen species for sulfur conversion. The synergistic interaction between In-TiO₂ and Bi₂MoO₆ provides a robust platform for efficient, selective, and durable desulfurization under mild conditions. These findings offer a mechanistic framework for designing next-generation S-scheme photocatalysts for environmental remediation and energy-related applications.