Ta 3 N 5 nanoparticles/TiO 2 hollow sphere (0D/3D) heterojunction: facile synthesis and enhanced photocatalytic activities of levofloxacin degradation and H 2 evolution.

Active removal of recalcitrant antibiotic contaminants for wastewater purification and hydrogen evolution from water splitting using hollow-structured photocatalysts has attracted considerable interest in the field of environmental governance and energy conversion. Herein, 0D Ta3N5 nanoparticles anchored on 3D TiO2 hollow nanosphere composites (0D/3D Ta/Ti) were designed and fabricated via a feasible surface self-assembly process for the first time. Various techniques were employed to characterize the structure and optical properties of the as-prepared samples. The photocatalytic activities of Ta3N5/TiO2 hybrids were systematically evaluated via both photodegradation of levofloxacin (LEV) and water splitting for hydrogen evolution under solar light irradiation. The degradation results showed that the x-Ta/Ti composites exhibit remarkably better performances for LEV degradation than pristine TiO2. The 3 wt% Ta3N5 nanoparticle-loaded hollow TiO2 composite material exhibited optimal photocatalytic activity (92.79%), and its degradation rate constant was 3.04 times that of TiO2. Simultaneously, the 3-Ta/Ti composite also possessed high ability to degrade other antibiotics such as ciprofloxacin (CIP) and tetracycline hydrochloride (TCH) and colored organic dyes such as Rhodamine B (RhB). Besides, x-Ta/Ti composites exhibited higher photocatalytic hydrogen evolution activities compared with TiO2 hollow spheres. The efficient charge transfer and separation between the close heterogeneous interfaces, broadened spectral response range and improved specific surface area were mainly responsible for the superior photocatalytic performance of the x-Ta/Ti nanocomposite. Our study provides an effective strategy for the design of hollow structure composite photocatalysts with excellent photocatalytic performances not only for pollutant removal, but also for efficient solar-to-fuel conversion.