Peroxymonosulfate activation over (Cu+ decorated g-C3N4)/Bi2WO6 composites with S-scheme heterojunction for RhB degradation

Abstract

Catalytic activation of peroxymonosulfate (PMS) is one of the important research areas in the development of advanced oxidation technology for wastewater treatment. At present, the development of high-performance catalysts for PMS activation has become a research hotspot. Herein, (Cu⁺ decorated g-C₃N₄)/Bi₂WO₆ ((Cu⁺/g-C₃N₄)/Bi₂WO₆) composite was prepared successively by calcination and solvothermal method, which was used in visible light-assisted PMS activation for the degradation of rhodamine B (RhB). The construction of S-scheme heterojunctions between Cu⁺ decorated g-C₃N₄ and Bi₂WO₆ facilitated the activation of PMS, leading to a RhB degradation ratio of 98.46 % within 50 min. The corresponding reaction kinetic was significantly improved by a factor of 2.32 and 7.94 compared with that of CCN and BWO, respectively. The enhanced performance of the (Cu⁺/g-C₃N₄)/Bi₂WO₆ can be attributed to the successful construction of S-scheme heterojunction, which facilitates the separation of photogenerated carriers and accelerates the PMS activation to produce abundant active species. Furthermore, the (Cu⁺/g-C₃N₄)/Bi₂WO₆ composites exhibit strong stability and reusability following three cycles. In addition, the intermediates produced during the RhB degradation process were investigated by liquid chromatograph mass spectrometer (LC-MS). This study provides a new insight into the preparation of S-scheme photocatalysts for the photocatalytic-PMS activation system that will achieve efficient removal of dyes from wastewater.