Construction of AgI@Br-Cu2O Composite with Improved Photocatalytic Performance and Stability Under Visible Light

In this study, spherical Br-Cu₂O was successfully synthesized by a one-step hydrothermal method, and AgI@Br-Cu₂O composite photocatalysts were prepared by loading AgI nanoparticles on them using liquid-phase deposition. The catalysts were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS), and electrochemical impedance spectroscopy (EIS) for their microscopic morphology and photoelectronic properties. The results showed that Br doping reduced the bandgap of Cu₂O, enhanced the visible light absorption, and improved the photocatalytic performance by promoting the formation of oxygen vacancies. Under the optimal composite ratio, 10% AgI@20% Br-Cu₂O showed excellent photocatalytic activity for the degradation of tetracycline under visible light irradiation, with efficiency of 85.7%. Superoxide radicals (·O₂⁻) were proven to be the main active species in the photocatalytic degradation process. Cycling stability tests revealed that 10%AgI@20%Br-Cu₂O maintained approximately 94.4% of its initial activity over five cycles, significantly outperforming AgI@Cu₂O. In summary, AgI@Br-Cu₂O composites show great potential for environmental remediation applications due to their excellent photocatalytic activity and stability.