Abstract: A novel and effective BiOCl_0.9I_0.1/x%β-Bi₂O₃ composite catalyst was synthesized through a precipitation method. The structure, morphology, and optical properties of the samples were certified by X-ray diffraction, UV-Vis diffuse reflectance, scanning electron microscopy, and X-ray photoelectron spectroscopic characterizations. Photocatalytic experiments demonstrated that the synthesized BiOCl_0.9I_0.1/x%β-Bi₂O₃ composite catalyst exhibited excellent photocatalytic performance toward the degradation of tetracycline hydrochloride (TCH) under simulated sunlight. Furthermore, the TCH degradation rate of BiOCl_0.9I_0.1/15%β-Bi₂O₃ increased by 27.6% and 61.4% compared with those of the pure BiOCl_0.9I_0.1 and pure β-Bi₂O₃, respectively. Due to the multiple vacancies and valence states possessed by BiOCl_0.9I_0.1/x%β-Bi₂O₃, namely Bi⁵⁺, Bi^(3-x)+, Bi⁵⁺-O, Bi³⁺-O, I^- and I₃^-, the charge separation in photocatalysis reactions can be effectively promoted. The Mott-Schottky measurements indicate that the conduction band (CB) level of BiOCl_0.9I_0.1/15%β-Bi₂O₃ becomes more negative relative to that of BiOCl_0.9I_0.1, guaranteeing an advantageous effect on the redox ability of the photocatalyst. This study provides a new bright spot for the construction of high-performance photocatalysts.

Key words: BiOCl_0.9I_0.1/β-Bi₂O₃, Degradation, Tetracycline hydrochloride, Photocatalysis, Simulated sunlight