Enhanced photocatalytic degradation of antibiotics in water over functionalized N,S-doped carbon quantum dots embedded ZnO nanoflowers under sunlight irradiation

By Yanning Qu, Xiaojiang Xu, R. Huang, W. Qi, R. Su, Zhimin He. Chemical Engineering Journal, 2020

163 citations recorded by the source corpus.

Abstract ZnO is widely used as a photocatalyst in industry, however, it is still a challenge to degrade refractory antibiotics in water. In this study, a novel surface-functionalized N,S-doped carbon quantum dot (N,S-CQD) was synthesized and embedded into ZnO for the formation of a new ZnO/N,S-CQDs hybrid nanoflower via one-pot hydrothermal process. The as-prepared ZnO/N,S-CQDs showed significantly enhanced photocatalytic activity under visible and near-infrared (NIR) light irradiation, in which 72.8% of MG was decomposed after 180 min under NIR light. In addition, approximately 92.9% and 85.8% of ciprofloxacin (CIP) were degraded by ZnO/N,S-CQDs under simulated sunlight for 20 min and natural sunlight for 50 min, respectively. Furthermore, the mechanism was investigated and the results show that the surface functionalization, electron transfer, up-converted luminescence properties of N,S-CQDs, together with the highly reactive facets of ZnO nanoflowers, made great contributions to the enhanced photocatalytic activity of ZnO/N,S-CQDs. Additionally, the results of active species trapping experiments indicated that the hydroxide free radicals, holes and superoxide radical anions all played certain roles in the photocatalytic reaction. Finally, ZnO/N,S-CQDs was employed for photodegradation of antibiotics in actual water, the degradation efficiency of antibiotics still remained above 60% after 120 min. We believe that the ZnO/N,S-CQDs nanoflower is a promising photocatalyst for the degradation of refractory antibiotics under sunlight irradiation. The relatively low cost and excellent photocatalytic performance of ZnO/N,S-CQDs is beneficial for industrial applications.

Subfields: Materials Chemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/4378f1a9ee212706435cdde99a6275f0015292c5