Facile solvothermal synthesis of CoO/BiOI flower-like nanocomposites for degradation of RhB under visible-light irradiation

In order to achieve effective electron-hole separation and improve the photocatalytic performance in the visible-light region, CoO/BiOI nanocomposites were successfully synthesized via a facile solvothermal method and studied their catalytic activity in dye degradation process. The morphological and compositional properties of the synthesized photocatalysts material were characterized by SEM, TEM, XRD, XPS, and FTIR. The optical properties of the as prepared composites were analyzed by UV-Vis. DRS. Electrochemical analysis was carried out to achieve rapid charge transfer. Uniform ultra-thin flower-like structure and high catalytic performance were observed for 40wt% CoO/BiOI nanocomposites. From XPS analysis, respective oxidation states of Bi, O, I, and Co were detected. The results indicated that flower-like 40 wt% CoO/BiOI nanocomposite exhibited high visible-light absorption, rapid photoelectrocatalytic removal of 92% RhB within 60 min under visible light, followed pseudo-first-order kinetics. Furthermore, good stability of the photocatalyst was also observed over five consecutive cycles. Growth and photocatalytic mechanisms were proposed to explain the high photoelectrochemical performances, and the materials are better for the environment and energy in wastewater purification.