Upgrading Type‐II Heterojunction to S‐Scheme Heterojunction for Enhanced Photocatalytic Toluene Oxidation Performance

ABSTRACT Construction of heterojunctions has been extensively applied to enhance the catalytic performance of TiO 2 ‐based semiconductor photocatalysts in the oxidation of volatile organic compounds (VOCs). However, improper charge transfer directions in type‐II heterojunctions often result in inadequate redox reactions for O 2 /·O 2 − and OH − /·OH at lower potentials. In this study, a three‐component heterojunction with multi‐stage S‐Scheme charge transfer was constructed by a self‐assembled growth strategy, where CeO 2 and WO 3 were strategically deposited onto TiO 2 nanosheets and applied to the photocatalytic oxidation of toluene. Catalytic performance evaluation revealed that the Ce‐W/TiO 2 heterojunction significantly enhanced the photocatalytic oxidation activity of toluene. Notably, Ce‐W/TiO 2 reached a mineralization rate of 98.4%, surpassing most other catalysts. Further systematic characterizations and theoretical calculations demonstrated that the incorporation of CeO 2 and WO 3 not only broadened the photoresponse range but also optimized the charge transfer and surface reaction kinetics, thereby enabling the highest photocatalytic toluene oxidation activity on Ce‐W/TiO 2 . This work highlighted the critical role of charge transfer pathways in TiO 2 ‐based semiconductor photocatalysts for toluene oxidation and provided valuable insights for the rational design of highly efficient photocatalysts for VOCs mineralization through heterojunction engineering.