Designing effective and stable S-scheme RGO/AgVO3/AgBr hybrid with enhanced photocatalytic performance

The low separation of photogenerated electron-hole pairs and cycle stability has been the main bottleneck which restricts the development of photocatalytic technology for water purification. Here, RGO/AgVO₃ composites were fabricated by photo-ultrasonic assisted reduction method, and AgBr nanoparticles were assembled on the surface of RGO/AgVO₃ via an in situ ion exchange method. A series of characterization and experimental results indicated that the introduction of RGO influenced the growth of crystal phase for AgVO₃ nanorods, resulting that AgVO₃ nanorods became thicker and shorter with the increase in RGO content. Moreover, RGO could also work as a bridge to promote the migration of electrons, leading different improvement for photocatalytic activity. Furthermore, in situ growth of AgBr on the surface of AgVO₃ nanorods could prevent its agglomeration and exfoliation, thus improving the photocatalytic activity and cycle stability of composites. RGO_1%/AgVO₃/AgBr_30% exhibited excellent photocatalytic activity and stability for methylene blue (MB) degradation due to its unique structure, and its removal ratio reached at 96.2% within 50 min. Meanwhile, the separation of photogenerated electron-hole pairs of AgVO₃ was markedly improved due to the introduction of RGO and AgBr. Based on the trapping experiments and theoretical calculation of band gap, a possible S-scheme photocatalytic mechanism for improved photocatalytic activity was proposed.