Novel S-scheme 2D/2D BiOBr/g-C3N4 heterojunctions with enhanced photocatalytic activity

The design and construction of heterojunction photocatalysts, which possess a staggered energy band structure and appropriate interfacial contact, is an effective way to achieve outstanding photocatalytic performance. In this study, 2D/2D BiOBr/g-C3N4 heterojunctions were successfully obtained by a convenient in situ self-assembly route. Under simulated sunlight irradiation, 99% of RhB (10 mg·L−1, 100 mL) was efficiently degraded by 1.5-BiOBr/g-C3N4 within 30 min, which is better than the performance of both BiOBr and g-C3N4, and it has superior stability. In addition, the composite also exhibits enhanced photocatalytic activity for H2 production. The enhanced activity can be attributed to the intimate interface contact, the larger surface area, and the highly efficient separation of photoinduced electron–hole pairs. Based on the experimental results, a novel S-scheme model was proposed to illuminate the transfer process of charge carriers. This study presents a simple way to develop novel step-scheme photocatalysts for environmental and related applications.