A novel n-CeO2/n-CdO heterojunction nanocomposite for enhanced photodegradation of organic pollutants under visible light irradiation

In this study, a series of novel visible light driven n-CeO2/n-CdO heterojunction (CeO2/CdO) nanocomposites were successfully fabricated by simple ultrasonication method. Several characterization tools including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectroscopy (UV-DRS), etc., were utilized to investigate the physicochemical properties of the catalyst and confirm the formation of heterojunction. Under visible light irradiations, the photocatalytic activities of the as-prepared CeO2/CdO nanocomposites were evaluated by degrading of Congo red (CR) and Rhodamine B (RhB) solutions. As a result, the CeO2/CdO (mass percentage ratio 1:3) nanocomposite displays remarkable performance for CR and RhB degradation. The enhancement in the photocatalytic performance of CeO2/CdO (1:3) nanocomposite can be attributed not only to the strong visible-light absorption region, separating the photogenerated electronhole pairs but also to the formation of n-n type heterojunction. The results also indicate that the CeO2/CdO (1:3) nanocomposite has good stabilization and high reusability. In addition, the mechanism is proposed for the coupled semiconductors and possible reasons for the enhancement of visible-light photocatalytic efficiency are also discussed. This work can provide a new gateway to fabricate visible photocatalysts and promising candidate catalysts for poisonous wastewater treatment in the near future. (C) 2019 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.