Enhanced photoactivity of Sn-doped BiOI microspheres for antibiotic degradation

The widespread use of antibiotics such as tetracycline has led to significant risks to both environmental sustainability and public health due to their persistence in natural water systems. In this study, Sn-doped BiOI microspheres were successfully synthesized through a simple one-step hydrothermal method to achieve enhanced photodegradation of tetracycline in aqueous solution. After 40 min of visible light irradiation, the optimal Sn-doped BiOI photocatalyst exhibited an exceptional tetracycline degradation efficiency of 82.8 %, significantly surpassing the 56.0 % efficiency of pure BiOI. To understand the origins of the enhanced catalytic behavior, a series of characterization techniques, including XRD, SEM, XPS, UV–Vis DRS, PL, and electrochemical measurements, were performed to investigate the crystal structure, morphology, surface states, light absorption properties, and charge carrier recombination and separation dynamics of the catalysts. These analyses demonstrated that Sn doping substantially modified the microscopic structure, morphology, and optical properties of BiOI, thereby greatly improving its photocatalytic efficiency. Further analysis of Sn doping effects demonstrated significant enhancement in transport and separation of photocarriers within BiOI microspheres, thereby leading to substantially improved photocatalytic performance under visible light.