摘要
In this study, the manganese dioxide (MnO 2 ) nanosheets were successfully embedded onto boron and sulfur co-doped g-C 3 N 4 (CNBS) nanotubes to construct the flower-like core–shell CNBS@MnO 2 heterojunction with Z-scheme structure for the enhanced photodegradation of diclofenac (DCF) in the presence of peroxymonosulfate (PMS) and 460-nm visible light. The CNBS@MnO 2 provides large specific surface area and reduced interfacial resistance for rapid electron transport. Moreover, the redox cycling of Mn species effectively activates PMS to produce sulfate radicals for DCF photodegradation. The PMS-based photodegradation of DCF over CNBS@MnO 2 displays the excellent photodegradation performance after 15 min of irradiation, and the efficiency is highly dependent on initial pH, ion species, and concentrations of PMS and DCF. The CNBS@MnO 2 also shows its excellent stability and reusability over ten cycles. Besides, h + , O 2 ●− and SO 4 ●− are the dominantly reactive species for the enhanced degradation of DCF over Z-scheme CNBS@MnO 2 heterojunction. The possible reaction mechanism as well as the degradation pathway of DCF over CNBS@MnO 2 in the presence of PMS is also proposed. Results clearly highlight the superior photoactivity of Z-scheme CNBS@MnO 2 toward micropollutant degradation by PMS activation, which can open an avenue to fabricate the g-C 3 N 4 nanotube@metal oxide structure as an effective activator for water and wastewater purification.