Enhanced Visible-Light-Induced Photoactivity of Type-II CeO2/g-C3N4 Nanosheet toward Organic Pollutants Degradation

Abstract

Photodegradation has been considered as an efficient environmental remediation technology to eliminate organic pollutants from wastewater, and the calling for high-performance photocatalysts is endless. Herein, we developed an efficient solid-state thermolysis route for the mass production of type-II CeO₂/g-C₃N₄ nanosheet (CeO₂/CNNS) serving as efficient photocatalysts toward bisphenol A (BPA) degradation under visible light illumination. The microstructures, compositions, and optical properties of the obtained samples were characterized by multitechniques, and n–n heterojunction was verified to be perfectly formed in CeO₂/CNNS with an intimate contact interface. A total of 93.7% BPA was removed by the optimal CeO₂/CNNS composites after 80 min visible light irradiation, but only 65.0% and 14.4% of the BPA were removed by CNNS and CeO₂, respectively. It was mainly attributed to the matched energy levels of the CeO₂/CNNS heterostructure, which facilitated the migration and separation of photoinduced charge carriers. Combining trapping experiments and ESR analysis, the results indicated that holes (h⁺) and superoxide radicals (O₂•–) dominated the photodegradation reactions. As expected, the CeO₂/CNNS composites still remained stable up to the sixth cycling test, implying the possible application for actual wastewater treatment. This work highlighted the mechanism of CeO₂/CNNS composites and gained a deeper insight for the fabrication of heterojunction catalysts and their application in environmental pollution management.