One-step synthesis of reduced graphene oxide based ceric dioxide modified with cadmium sulfide (CeO2/CdS/RGO) heterojunction with enhanced sunlight-driven photocatalytic activity.

Heterojunction photocatalyst with efficient photocatalytic performance can remarkably promote the separation of photogenerated charge carriers. Herein, a ternary photocatalyst, reduced graphene oxide (RGO) based CeO2 modified with CdS (CeO2/CdS/RGO), was synthesized by a simple one-step hydrothermal method as a bifunctional catalyst for both photodegradation and photoreduction. The ternary composite exhibited a 90.04% photodegradation efficiency to ciprofloxacin (CIP) under simulated sunlight irradiation for 2 h, much higher than CeO2 (54%). Moreover, CeO2/CdS/RGO showed broad applicability to the photodegradation of organic pollutants, including norfloxacin (NFX), tetracycline (TC), methylene blue (MB), rhodamine B (RhB), methyl violet (MV), methyl orange (MO) and reactive blue BES (RB). Besides, CeO2/CdS/RGO exhibited a 100.00% photoreduction efficiency to Cr(VI) within 60 min. The improvement of the photocatalytic performance is ascribed to the modification of CeO2 with CdS, which improves the separation efficiency of photogenerated carriers. Also, the modification with RGO inhibits the agglomeration of CeO2, improves the adsorption capacity toward pollutants and provides another nanochannel to separate photogenerated electron-hole (e--h+) pairs. Additionally, the photocatalytic mechanism of CeO2/CdS/RGO is explored. It is expected that this work would provide a promising way to construct efficient and versatile RGO-based photocatalysts applied to environmental remediation.