A heterojunction photocatalyst constructed by the modification of 2D-CeO2 on 2D-MoS2 nanosheets with enhanced degrading activity

A new 2D/2D heterojunction of MoS2/CeO2 is successfully prepared by a facile hydrothermal method. The MoS2/CeO2 heterojunction demonstrates superior photocatalytic performance for the degradation of ciprofloxacin (CIP) to that of pure MoS2 and CeO2. The enhanced degradation efficiency of the MoS2/CeO2 heterojunction is on account of the 2D/2D structure, which not only accelerates the interfacial charge separation but also endows the heterojunction with numerous reactive sites to facilitate the degradation reaction. Meanwhile, the Ce4+ ions in 2D CeO2 serve as the redox centers and utilize the photogenerated carriers to generate more oxygen vacancies. In addition, this paper also carefully discusses the possible photocatalytic reaction mechanisms for the transfer behaviors of charge carriers, generation of reactive species and intermediate degradation products by electrochemical impedance spectroscopy (EIS), electron spin resonance (ESR) and HPLC-MS analysis. This work may provide a promising approach for synthesizing 2D/2D heterojunctions in photocatalytic degradation.