Study on the mechanism of Bi2WO6/ NixMo1-xS2 heterojunction photocatalysis for efficient degradation of TCH

To address the limited photocatalytic efficiency of single semiconductors in antibiotic degradation, this study successfully synthesized Bi 2 WO 6 /Ni 0 . 08 Mo 0 . 92 S 2 Z-Scheme heterojunction photocatalysts via a hydrothermal approach. Comprehensive characterizations including XRD, SEM, HRTEM, and BET confirmed the effective construction of the heterojunction. The optimal composite with 8% Bi 2 WO 6 loading exhibited a 38% increase in specific surface area and maintained coherent interfacial contact between components. Under simulated sunlight irradiation, this composite achieved 89.98% degradation of 60 mg/L tetracycline hydrochloride within 150 minutes, which was 8.65 and 1.58 times higher than that of pure Bi 2 WO 6 and Ni 0 . 08 Mo 0 . 92 S 2 , respectively. Mechanistic investigations revealed that the enhanced performance originated from narrowed bandgap, suppressed electron-hole pair recombination, optimized interfacial electron transfer, and degradation processes dominated by superoxide radicals and photo-induced holes—findings validated by scavenger experiments and ESR analysis. Additionally, the composite demonstrated good cyclic stability, retaining 78.6% of its initial efficiency after three consecutive cycles, along with broad-spectrum activity towards various antibiotics. This work provides a promising strategy for the rational design of high-performance heterojunction photocatalysts for efficient water purification.