Visible-light-driven Bi2O3/WO3 composites with enhanced photocatalytic activity

Abstract

Semiconductor heterojunctions (composites) have been shown to be effective photocatalytic materials to overcome the drawbacks of low photocatalytic efficiency that results from electron–hole recombination and narrow photo-response range. A novel visible-light-driven Bi₂O₃/WO₃ composite photocatalyst was prepared by hydrothermal synthesis. The composite was characterized by scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area, Raman spectroscopy, photoluminescence spectroscopy (PL) and electrochemical impedance spectroscopy (EIS) to better understand the structures, compositions, morphologies and optical properties. Bi₂O₃/WO₃ heterojunction was found to exhibit significantly higher photocatalytic activity towards the decomposition of Rhodamine B (RhB) and 4-nitroaniline (4-NA) under visible light irradiation compared to that of Bi₂O₃ and WO₃. A tentative mechanism for the enhanced photocatalytic activity of the heterostructured composite is discussed based on observed activity, band position calculations, photoluminescence, and electrochemical impedance data. The present study provides a new strategy for the design of composite materials with enhanced visible light photocatalytic performance.