Construction of a flower-like S-scheme Bi2WO6/BiOCl nano-heterojunction with enhanced visible-light photocatalytic properties

Abstract

A novel flower-like S-scheme Bi₂WO₆/BiOCl nano-heterojunction is successfully fabricated by a simple one-pot hydrothermal method. With the construction of the flower-like structure and S-scheme heterojunction, the Bi₂WO₆/BiOCl-3 nano-heterojunction displays an excellent photocatalytic activity with a 98.6% degradation rate for rhodamine B (RhB) solution under visible light illumination, which is 2.51 and 2.91 times higher than those of Bi₂WO₆ and BiOCl catalysts, respectively. In order to interpret the photocatalytic process, pure Bi₂WO₆ and BiOCl are investigated by optical and electrochemical measurements, which obtained the band gap of Bi₂WO₆ (2.92 eV) and BiOCl (3.35 eV), the conduction band potential (0.07 eV) of the n-type semiconductor Bi₂WO₆ and the valence band potential (0.34 eV) of p-type semiconductor BiOCl. According to the radical species trapping experiments, a probable photocatalytic mechanism is discussed in detail. For the development and design of S-scheme heterojunction photocatalysts in wastewater treatment, the Bi₂WO₆/BiOCl nano-heterojunction is a promising photocatalytic material.