Direct Z-scheme Ag2WO4/BiOCl composite photocatalyst for efficient photocatalytic degradations of dissolved organic impurities

Abstract

In this work, Ag2WO4/BiOCl composite photocatalyst was successfully prepared by a facile coprecipitation. The crystalline structures, morphologies, optical properties and photocatalytic activities of photocatalysts have been investigated via XRD, SEM, EDX spectrum, UV–vis diffuse reflectance spectroscopy, PL spectra and electrochemical measurement. After depositing Ag2WO4 onto the surface of BiOCl, its phase transformed from α-Ag2WO4 to β-Ag2WO4 and its morphology changed from nanorods to nanoparticles. Ag2WO4 nanoparticles easily grew and assembled on the surface of flower-like BiOCl nanosheets because of its large surface area, which remarkably promote more light scattering/reflection to broaden light absorption. The Ag2WO4/BiOCl Z-scheme heterojunction shows higher photocatalytic activity towards degradation of Rhodamine B (RhB) than that of pure BiOCl, the best photocatalytic efficiency is achieved by the10% Ag2WO4/ BiOCl heterojunction (81.3%) far surpasses that of pure BiOCl (52.1%) within 25 min under stimulated solar irradiation, owing to effectively improved charge separation of the photogenerated electron-hole pairs. The possible charge transfer processes and mechanism for photocatalytic degradation were proposed.