Fabrication of a three-dimensional BiOBr/BiOI photocatalyst with enhanced visible light photocatalytic performance

Three-dimensional (3D) BiOBr/BiOI hierarchical microsphere photocatalysts were successfully synthesized via a facile one-pot solvothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and N2 adsorption-desorption isotherms. The photocatalytic activity was evaluated by the photocatalytic degradation of Rhodamine B (RhB) and tetracycline (TC) under visible light irradiation (λ>420 nm). The 50% BiOBr/BiOI composite showed a higher photocatalytic removal efficiency of RhB and TC than 10% and 90% BiOBr/BiOI composites. RhB (C0=15 mg/L) was degraded completely within 40 min and over 83% of TC (C0= 40 mg/L) was degraded within 50 min using a catalyst quantity of 0.4 g/L of 50% BiOBr/BiOI. The enhanced photocatalytic activity of the 50:50 composite was attributed to effective separation of photogenerated carriers and the balance between enhanced visible light absorption and decreased valence band (VB) edge potential.