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

Abstract

As a new bismuth-based photocatalytic material, Bi₂WO₆ 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 Bi₂WO₆/Bi₂S₃ nanocomposite constituted with nanosheets is prepared via a two-step hydrothermal process. Because of high crystallization and large specific surface area of the nanocomposite, the high separation rate of photogenerated carriers induced by the Z-scheme Bi₂WO₆/Bi₂S₃ heterojunction, and formation of abundant holes and ·O₂⁻ radicals, the Bi₂WO₆/Bi₂S₃ nanocomposite with 3 wt% Bi₂S₃ 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 Bi₂WO₆, respectively. The Bi₂WO₆/Bi₂S₃ 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.