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

Abstract

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.