TiO2 nanodots anchored on nitrogen-doped carbon nanotubes encapsulated cobalt nanoparticles as photocatalysts with photo-enhanced catalytic activity towards the pollutant removal

Constructing hierarchical structure is an effective approach to improve the activities of catalysts. Herein, a novel hierarchical structure of TiO 2 nanodots anchored on N-doped carbon nanotubes encapsulated Co nanoparticles (TiO 2 /Co@NCT) was synthesized by a simple pyrolysis method. Their catalytic performances were examined in the oxidative and light-assisted degradation of recalcitrant pollutants in the presence of the peroxymonosulfate (PMS). The Orange II removal efficiency within 15 min reached about 98.48% in TiO 2 /Co@NCT/PMS system. In this system, Co 0 is used to react with PMS to generate free radicals for the degradation of dyes. The carbon shell benefits the adsorption of dyes and prevents the catalysts from dissolving in the solution. Besides, under light irradiation, TiO 2 nanodots can be excited to generate photo-induced electrons, which can reduce inner Co 2+ to Co 0 in the degradation process, thus TiO 2 /Co@NCT exhabited high activity and outstanding stability in degradation process. The as-prepared TiO 2 /Co@NCT catalyst showed efficient degradation and superior stability, which would make it a great promise in practical applications for sewage treatment.