Enhanced performance for dyes degradation over ZnWO4/BiPO4 heterojunction

Abstract

Although pure BiPO₄ and ZnWO₄ exhibit limited degradation efficiency for Rhodamine B (RhB), methyl blue (MB), and basic fuchsin (BF), the degradation rates of the BiPO₄ and ZnWO₄ composite (2ZW:BP) were significantly enhanced. Specifically, the rates were 133.8 and 99.1 times higher for RhB, 6.33 and 18.51 times higher for MB, and 18.3 and 19.12 times higher for BF, compared to BiPO₄ and ZnWO₄, respectively. The 2ZW:BP composite achieved degradation efficiencies of 91.4%, 92.8%, and 96.5% for RhB, MB, and BF within 100 min, 5 h, and 3 h under irradiation with a 5W LED lamp. Scanning electron microscopy (SEM) analysis revealed that although both BiPO₄ and ZnWO₄ exhibit rod-like morphologies, the ZnWO₄/BiPO₄ heterostructures formed through one-step hydrothermal recombination were sheet-like. This morphological transformation was accompanied by increased oxygen vacancies, enhanced charge-hole separation efficiency, a broader light absorption range, and improved dye adsorption rates, thereby significantly enhancing the photocatalytic performance of ZnWO₄/BiPO₄.