Engineering Z-scheme silver oxide/bismuth tungstate heterostructure incorporated reduced graphene oxide with superior visible-light photocatalytic activity

Abstract

Photocatalytic degradation of multiple organic contaminants has received extensive research attention and rational design of visible-light driven photocatalyst has been considered as an efficient approach. In this study, a visible-light Ag2O/Bi2WO6 heterostructure incorporated reduced graphene oxide (ABW-RGO) composite photocatalyst was prepared through a facile hydrothermal method for the first time and exhibited synergetic degradation behavior for contaminants in aqueous solutions. Under visible light, Tetracycline antibiotics has degraded 95.3% within only 40 min, and dye pollutants including Crystal Violet (cationic dye) and Congo Red (anionic dye) reached over 98.5% decomposition. The synthesized composite is also highly efficient in a wide pH range and multi-components system, maximizing the utilization of common sunlight, which make it suitable for industrial wastewater. The reactive oxidant species (ROS) experiment and electron spin resonance (ESR) measurement revealed the critical role of hydroxyl and superoxide radicals, clarifying the degradation pathway and mechanism analysis. The superior photocatalytic activity could be attributed to the formation of effective Z-scheme heterostructure and the excellent sorption capacity and conductivity of reduced graphene oxide. This research provides the design pathway to a novel catalyst using semiconductors composite and graphene support material, which can be extended to the energy-saving treatment of various organic pollutants.