Hierarchical Bi2WO6/Bi2S3 heterojunction nanocomposite facilitating photocatalytic degradation of organic pollutants

Abstract

As a new bismuth-based photocatalytic material, Bi 2 WO 6 has shown superiority in photocatalytic decomposition of organic pollutants, because of its special layered structure, wide light response range, non-toxicity, and low cost. Nevertheless, its photocatalytic performance is limited by low visible light utilization efficiency and high recombination efficiency of photogenerated electrons and holes. Herein, a hierarchical Bi 2 WO 6 /Bi 2 S 3 nanocomposite constituted with nanosheets is prepared via a two-step hydrothermal process. Because of high crystallization and large specific surface area of the nanocomposite, high separation rate of photogenerated carriers induced by Z-scheme Bi 2 WO 6 /Bi 2 S 3 heterojunction, and formation of abundant holes and •O₂ -radicals, the Bi 2 WO 6 /Bi 2 S 3 nanocomposite with 3 wt% Bi 2 S 3 shows high rhodamine B and tetracycline removal rates of 91% and 88% under visible light irradiation, which are 1.60 and 1.87 times those of pure Bi 2 WO 6 , respectively. The Bi 2 WO 6 /Bi 2 S 3 nanocomposite also exhibits high photocatalytic stability even after five consecutive photocatalytic degradation experiments. This work presents a novel heterojunction nanocomposite structure for efficient degradation of organic pollutants.