Anchoring Ceria Nanoparticles on Reduced Graphene Oxide and Their Enhanced Photocatalytic and Electrochemical Activity for Environmental Remediation

Here, we report the synthesis of CeO 2 and a reduced graphene oxide (rGO)/CeO 2 nanocomposite prepared through a facile single-step hydrothermal procedure. Modern measurement techniques, including x-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution (HR)-TEM, scanning electron microscopy (SEM), UV–Vis spectroscopy, photoluminescence (PL) spectroscopy, and photocatalytic and electrochemical measurements, were utilized to analyze the as-obtained CeO 2 nanoparticles (NPs) and rGO/CeO 2 nanocomposite. XRD patterns for the synthesized CeO 2 and rGO/CeO 2 revealed a pure cubic phase of CeO 2 . Field emission scanning electron microscopy (FE-SEM) images showed nanocrystalline CeO 2 NPs almost uniformly anchored on the rGO surface. The results of UV–Vis absorption spectra of the synthesized nanocomposite showed a prominent red shift of the optical absorption edge. The photocatalytic performance of the prepared CeO 2 and rGO/CeO 2 was examined for rhodamine B (RhB) dye degradation under sunlight irradiation. The rGO/CeO 2 nanocomposite demonstrated high photocatalytic activity against RhB dye in 100 min under sunlight irradiation. This enhancement was attributed to the significant suppression of the recombination of photo-generated electron–hole pairs and rapid transport through rGO sheets, and the lower band gap energy of the rGO/CeO 2 nanocomposite. The electrochemical characteristics of the prepared CeO 2 nanoparticles and rGO/CeO 2 nanocomposite were examined by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The results indicated that the rGO/CeO 2 nanocomposite showed better capacitive behavior than pure CeO 2 NPs, possibly owing to the excellent electrical conductivity and substantial specific surface area attributable to rGO. The desirable features attained in the rGO/CeO 2 nanocomposite make it suitable for use in applications such as environmental pollution remediation and electrochemical energy storage.