Enhanced photocatalytic performance of Ag 2 O/BiOF composite photocatalysts originating from efficient interfacial charge separation

Previous studies have well established that the photocatalytic performance of BiOF is greatly inhibited by its inherent drawbacks, which are the wide band gap and high recombination of photo-generated charge carriers. Therefore, it is necessary to promote the photocatalytic activity of BiOF. In this work, a series of novel Ag2O/BiOF composites were prepared by a facile precipitation method and characterized by X-ray diffractometry (XRD), UV–vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), surface photovoltage (SPV) spectroscopy, and electron spin-resonance (ESR) spectroscopy. The photocatalytic characteristics of Rhodamine B (RhB) discoloration under simulated sunlight and visible-light irradiation were studied. The results revealed that the sample with 1.0% molar ratio of Ag/Bi displayed the best photocatalytic performance towards RhB discoloration and all the studied composites in this work displayed a higher photocatalytic activity than the bare BiOF. Based on the results of “band edge potential” of Ag2O and BiOF, SPV and ESR, charge separation and transportation mechanisms are suggested. Under simulated sunlight illumination, the charge separation and transport mechanism of the photo-induced charge pairs followed a Z-scheme.