Engineering Cd-Doped CeO2/rGO Nanocomposites: Optical Characterization and Photocatalytic Degradation of Methyl Orange

Abstract

This study reports the synthesis and comprehensive characterization of a novel 5% cadmium-doped cerium oxide/reduced graphene oxide (5% Cd-CeO2/rGO) nanocomposite for the enhanced visible-light-driven photocatalytic degradation of methyl orange (MO). The nanocomposite was prepared using a simple co-precipitation method followed by thermal reduction, which integrates the excellent electron-transport properties of reduced graphene oxide (rGO) with the oxygen-vacancy-rich characteristics of Cd-doped CeO2, resulting in improved photocatalytic performance. The successful synthesis of the nanocomposite and the direct interaction between the rGO sheets and ultrafine CeO2 nanoparticles were verified through structural and morphological analyses using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). XPS results indicated an increase in the Ce3+ concentration and oxygen vacancy density after Cd doping and rGO incorporation, both of which play a crucial role in enhancing photocatalytic activity. Under visible-light irradiation, the 5% Cd-CeO2/rGO nanocomposite exhibited substantially higher photocatalytic activity and methyl orange (MO) degradation efficiency than pristine CeO2 and reduced graphene oxide (rGO). The improved photocatalytic performance demonstrates the beneficial role of combining metal-ion doping with conductive carbon supports to facilitate charge separation and electron transport in semiconductor photocatalysts. The developed nanocomposite also shows promising potential for the design of next-generation semiconductor-based materials for photocatalytic, energy conversion, and optoelectronic applications.