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

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.