Synthesis, characterization and photocatalytic activity of visible-light-driven reduced graphene oxide-CeO2 nanocomposite

Reduced graphene oxide (RGO) and CeO2 nanocomposite fabricated by a facile hydrothermal method was studied as a photocatalyst for the degradation of methylene blue (MB) under natural sunlight. The reduction of graphene oxide and decoration of CeO2 nanocubes was accomplished simultaneously in one hydrothermal step. The structural, optical and photocatalytic properties of synthesized samples were probed by X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra and photoluminescence spectra. RGO/CeO2 nanocomposite exhibited distinctive structural features comprising well-dispersed CeO2 nanocubes on the RGO surface without any agglomeration. RGO/CeO2 nanocomposite displayed a great MB absorptivity, significant band gap narrowing and photoluminescence quenching phenomenon concurrently, which was ascribed to unique properties of RGO sheets. The photocatalytic activity results revealed that there was a remarkable enhancement in reaction rate with RGO/CeO2 nanocomposite in comparison to its counterparts (Blank CeO2 and CNT/CeO2 nanocomposite). The degradation efficiency of RGO/CeO2, CNT/CeO2 and CeO2 was found to be 91.2, 75 and 64 % within 180 min respectively.