Visible light-driven S-scheme ZnS/OVs-BiOCl heterojunctions for CO2 reduction and pollutants degradation

Abstract

Construction of heterojunctions and introduction of oxygen vacancies (OVs) are effective approaches to enhance photocatalytic performance of BiOCl. In this study, S-scheme ZnS/OVs-BiOCl heterojunctions was prepared. The presence of ZnS influences the crystal growth of BiOCl and promotes the formation of OVs. Ultraviolet photoelectron spectroscopy (UPS) was employed to investigate the work functions of BiOCl and ZnS, providing insights into the electron transfer mechanisms. In-situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) reveals the dynamic process of CO₂ conversion to CO. Electron paramagnetic resonance (EPR) spectroscopy was employed to investigate the active radicals involved in the photocatalytic degradation process. The synergistic effect of the internal electric field (IEF) and OVs enhances the separation of photoinduced charges and light absorption capability of BiOCl. Under visible light irradiation, the rate of CO₂ conversion to CO on the BOC-7 sample (the mass ratio of ZnS/BiOCl is 7 %) is 2.53 times of that on the reference BiOCl. Furthermore, versatility of the photocatalyst was investigated by examining photocatalytic degradation of Rhodamine B (RhB), Ciprofloxacin (CIP) and Moxifloxacin (MXF) on the photocatalyst under visible light illumination. Under visible light irradiation, the degradation rate constant of RhB, CIP and MXF on the BOC-7 sample is 6.08, 2.49, and 3.67 times of that over the reference BiOCl, respectively. This study provides a rational strategy for the development of high-performance BiOCl photocatalysts for environmental remediation.