3D reduced graphene oxide aerogel-mediated Z-scheme photocatalytic system for highly efficient solar-driven water oxidation and removal of antibiotics

The construction of natural photosynthesis-inspired Z-scheme tandem system has been considered as a promising strategy to fulfill efficient electron-hole separation and charge transportation in composite photocatalysts, providing a unique opportunity to achieve improved solar-driven photocatalytic water splitting performance superior to conventional heterojunctions. The presence of an ideal electron mediator is critical to promote effective electron transfer in Z-scheme semiconductor photocatalytic systems. Herein, for the first time, we report the fabrication of CeVO4/three-dimensional (3D) reduced graphene oxide (RGO) aerogel/BiVO4 ternary composites and their use as photocatalysts for visible-light-driven water oxidation and tetracycline (TC) degradation. As-prepared hybrid materials exhibit well-organized heterostructures where two vanadates with different dimensional features are surrounded by 3D aerogel networks. Under visible light irradiation, the optimal composite material revealed highly improved photocatalytic activity both in oxygen evolution from water splitting and TC degradation. The enhancement in photocatalytic efficiency is assumed to come from illuminated Z-scheme CeVO4/3D RGO/BiVO4 configuration, in which conductive 3D RGO aerogel functions as an effective electron mediator and builds the bridge between two vanadates, offering a tandem channel for more efficient charge transfer in two semiconductors. This work may provide a new clue for the design of all-solid-state Z-scheme composite photocatalytic materials in energy and environmental applications.