Interfacial Charge Transfer Effect of 2D/2D g-C3N4/BiOCl S-scheme Heterojunctions for Enhanced Removal of Dyes in Wastewater

Rational structural design of S-scheme heterojunctions in semiconductor-based photocatalysts constituted a pivotal strategy for optimizing their photocatalytic performance through efficient charge carriers separation and enhanced redox capability. Herein, a novel two-dimensional 2D/2D heterostructure is successfully constructed by integrating bismuth oxychloride (BiOCl) nanosheets onto g-C 3 N 4 nanosheets, which significantly enhances the interfacial contact area between these two components and facilitates the migration of photogenerated charge carriers by forming a built-in electric field. Specifically, thiourea, urea, and melamine are employed as the precursor to prepare a series of g-C 3 N 4 /BiOCl photocatalysts, denoted as T-CN/BiOCl, U-CN/BiOCl, and M-CN/BiOCl, respectively. Benefiting from the excellent hydrophilic characteristics, wide photoresponse ranges and efficient interfacial charge transfer, M-CN/BiOCl displays exceptional degradation performance for both cationic rhodamine B (RhB) dyes and anionic methyl orange (MO). Under simulated sunlight irradiation, the photocatalytic degradation of RhB (20 mg/L) and MO (20 mg/L) can exhibit distinct kinetics, with complete removal achieves in 10 min and 100 min , respectively. Notably, the degradation rate constants of RhB demonstrate the remarkable superiority, being 29.2-fold and 475.2-fold higher than those of MO under simulated sunlight and visible light irradiation.