Highly Efficient Photocatalytic Degradation of Tetracycline Antibiotics by BiPO4/g-C3N4: A Novel Heterojunction Nanocomposite with Nanorod/Stacked-like Nanosheets Structure.

The use of semiconductors for photocatalytic degradation of organic pollutants has garnered considerable attention as a promising solution to environmental challenges. Compared to TiO2, BiPO4 exhibits superior photocatalytic activity. However, its large band gap restricts its light absorption to the UV region. One effective technique for extending BiPO4's absorption wavelength into the visible spectrum is the construction of the heterostructure. This study aimed to synthesize monodisperse BiPO4 nanorods via a solvothermal approach and fabricate BiPO4/g-C3N4 heterojunctions with varying loadings through in situ deposition. Tetracyclines were employed as the target pollutant to evaluate the photocatalytic performance and stability of the prepared materials. The results indicated that 5 wt% of composite exhibited better photocatalytic performance than single catalysts, which showed the highest photodegradation efficiency of approximately 98% for tetracyclines. The prepared bi-photocatalyst presented favorable stability under sunlight irradiation, the photocatalytic activity of which remained almost unchanged after four cycles. The enhanced photocatalytic activity was attributed to the synergistic effect. Additionally, the possible degradation mechanism was elucidated utilizing the semiconductor energy band theory. Overall, this work presents new perspectives on synthesizing innovative and efficient visible-light-driven photocatalysts. It also offers a mechanistic analysis approach by integrating theoretical calculations with experimental observations.