Enhanced photocatalytic O2 activation by the synergy of efficient oxygen adsorption and interfacial charge separation: A case of Bi3O4Br/rGO van der Waals heterojunction

Herein, a novel 2D/2D van der Waals (VDW) heterojunction of oxygen-vacancy-rich Bi3O4Br load reduced graphene oxide (rGO) (Bi3O4Br/rGO) was used to reveal the synergy of efficient oxygen adsorption and interfacial charge separation. The performance of Bi3O4Br/rGO was evaluated by degrading tetracycline (TC), ciprofloxacin (CIP), 2,4-dichlorophenoxyacetic acid (2,4-D) and ranitidine hydrochloride (RAN) under visible light, which were 2.3, 2.6, 2.5 and 4 times higher than that of Bi3O4Br, respectively. Furthermore, Bi3O4Br/rGO displayed 4 times enhanced O2− production ability than Bi3O4Br. The improvement of photocatalytic efficiency could be ascribed to the better chemisorbed oxygen and lower recombination rate of photogenerated electron-holes. More importantly, its interfacial charge migration pathway was unraveled: The electrons are efficiently transferred from Bi3O4Br to rGO through VDW heterojunction interface thus resulting in more photogenerated carriers participating in reactions. This work may provide a feasible strategy to study on improving the molecular O2 activation efficiency for VDW heterojunction.