A Novel Bi2O3 Modified C-doped Hollow TiO2 Sphere Based on Glucose-derived Carbon Sphere with Enhanced Visible Light Photocatalytic Activity

Abstract

The hydrothermal method was used to synthesize carbon sphere, and the hard template synthesis method was used to prepared C-doped hollow TiO2 sphere (CHTS). Bismuth nitrate was used as bismuth source to modify CHTS. The composite material was oxidized in air atmosphere at 450℃ to obtain Bi2O3 modified C-doped TiO2 hollow spheres(BCHTS). The morphology, elemental composition and photocatalytic degradation efficiency of tetracyclines (TC) by BCHTS hollow spheres were characterized by various measurements. Additionally, the possible transformation pathways and degradation mechanism of tetracycline were revealed via LC–MS and trapping experiments. The experimental results show that the Bi nanoparticles are uniformly dispersed in the CHTS. The photocatalyst exhibits enhanced degradation rate of TC (98.4% under visible-light within 180 min and 99.4% under natural light within 50 min) for its structure and narrow bandgap (2.87 eV). After five degradation cycles, the photocatalyst still remains high removal rate of 96.4% for TC. The results indicate that the photocatalyst may be promising for degrading antibiotic residuals remains. According to the trapping experiment, OH and h+ have a certain role on the photodegradation process, while·O2− is the main active species for degrading TC.