Preparation of novel Ag/AgVO3/BiVO4 heterojunctions with significantly enhanced visible light-driven photocatalytic performance originated from Z-scheme separation of photogenerated charge pairs

Abstract

In this paper, Ag/AgVO3/BiVO4 heterojunctions were successfully prepared via a facile two-step method. The formation of Ag/AgVO3/BiVO4 heterojunctions can be confirmed by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). The separation properties of photogenerated carriers were studied by surface photovoltage spectroscopy (SPS) and electrochemical technology. The results show that the separation rate of photoinduced carriers of Ag/AgVO3/BiVO4 heterojunctions can be dramatically promoted. The photocatalytic activity of the sample was evaluated by abatement of rhodamine B (RhB) under visible light irradiation. The results display that the photocatalytic activity of Ag/AgVO3/BiVO4 heterojunctions exhibit improved photocatalytic performance for the RhB degradation. Trapping measurements confirm that holes and O2− play a significant role in degradation of RhB, which can be attributed to the existence of Ag0 in the samples. Based on all the characterization results, a Z-scheme mechanism of photogenerated charge separation and transfer was proposed. Moreover, the enhancement in photocatalytic performance of Ag/AgVO3/BiVO4 heterojunctions is related to the separation and transfer of photogenerated carriers.