Non-Metal Modified g-C3N4/WS2 Z-Scheme Heterojunction for Enhanced Degradation of Antibiotics under Visible Light

Abstract

The creation of 2D–2D heterojunctions has garnered significant interest for environmental applications due to their enhanced catalytic performance, particularly when heteroatoms are incorporated to modify their optical and electronic properties. In this study, a Z-scheme heterojunction composite, consisting of boron (B)-doped graphitic carbon nitride (g-C3N4) and tungsten disulfide (WS2), was developed through a simple and scalable method, and its potential for photocatalytic degradation of tetracycline (TC) and sulfamethoxazole (SMX) was evaluated. The as-synthesized 2D–2D heterojunction with optimal B content (designated BGCW-2) exhibited exceptional photocatalytic efficiency, removing 99% of both pollutants within 90 min under visible light. This impressive performance is attributed to enhanced electron transport, facilitated by N–B–N bridges in B-doped g-C3N4, and improved charge separation due to Coulombic interactions between B and nitrogen (N). Furthermore, BGCW-2 demonstrated excellent stability, maintaining its high photocatalytic activity after several reuse cycles with minimal loss in performance. Additionally, the degradation products were found to be non-toxic, confirming the environmental safety of the process. Moreover, by optimizing key operational parameters, such as catalyst concentration and pH, the degradation efficiency could be further enhanced. These findings highlight the significant potential of non-metal doping in boosting the photocatalytic properties of 2D–2D heterojunctions, offering an effective and sustainable solution for the environmental remediation of pharmaceutical-based pollutants.