Synthesis of novel ternary Bi2WO6/CeO2/g-C3N4 composites with enhanced visible light photocatalytic activity for removal of organic and Cr(VI) from wastewater

Abstract

In this study, novel ternary Bi2WO6/CeO2/g-C3N4 composites were synthesized successfully in this study, which exhibited enhanced visible-light photocatalytic activity for oxidization of rhodamine B (RhB) and tetracycline hydrochloride (TH) as well as reduction of Cr(VI). The characteristics of the as-prepared composites were investigated in detail by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectra (FT-IR), UV–vis diffuse reflectance spectra (UV-DRS), Photoluminescence spectra (PL), Electrochemical Impedance Spectroscopy (EIS) and Mott-Schottky curves. The results demonstrated that the ternary heterojunctions were formed between Bi2WO6, CeO2 and g-C3N4, which can narrow the band gap to improve separation and migration of photogenerated electrons-hole pairs, so that the lifetimes of photogenerated charge carriers were prolonged to involve in photocatalytic reaction. Therefore, Bi2WO6/CeO2/g-C3N4 can generate abundant free radicals under visible-light irradiation to enhance photocatalytic activity. BW/Ce/g-3 can degrade 99.24% of RhB in 75 min and 54.76% of TH in 105 min. More than that, BW/Ce/g-3 exhibited enhanced photocatalytic reduction for Cr(VI) (94.85%, 30 min). Meanwhile, the best synthesized condition was determined that the adding amount of CeO2 was 0.043 g and g-C3N4 was 0.02 g. This study not only provided a mothed to synthesize Bi2WO6/CeO2/g-C3N4 ternary heterojunctions, but also confirmed a photocatalyst for degrading both organic pollution and heavy metals wastewater.