CeOx/TiO2-yFy nanocomposite: An efficient electron and oxygen tuning mechanism for photocatalytic inactivation of water-bloom algae

Eutrophication raises a widespread problem for rivers and lakes all over the world, which serves as a seedbed for uncontrollable growth of harmful algae. Here, we prepare CeO_x/TiO_2-yF_y nanocomposites by a facile sol-gel method to offer an efficient solution for inactivation of harmful algae such as Microcystis aeruginosa with visible light irradiation. The results show that the nanocomposites hold ideal CeO_x coupling and F doping forms when the calcination temperature is 550?°C (CeO_x/TiO_2-yF_y-550). The CeO_x/TiO_2-yF_y-550 nanocomposite exhibits a higher light absorption capacity and lower recombination efficiency for photogenerated carriers in comparison to the CeO_x/TiO_2-yF_y nanocomposite. Moreover, it exhibits an excellent photocatalytic inactivation efficiency of 100% following 4?h irradiation. We also find that the photosynthetic efficiency of algal cells reduces in the inactivation process, and the electron transport process in the photosynthetic system is inhibited, which are ascribed to the formation of hydroxyl radicals (·OH) and superoxide radical (·O₂^-). Such an efficient photocatalytic inactivation performance for the CeO_x/TiO_2-yF_y-550 can be attributed to the outstanding contribution of ·O₂^- resulting from the electron and oxygen tuning by CeO_x coupling and F doping.