Synthesis and characterization of a quaternary nanocomposite based on TiO2/CdS/rGO/Pt and its application in the photoreduction of CO2 to methane under visible light

Abstract

‘Together we are stronger’ In this work, the preparation of the quaternary nanocomposite TiO₂/CdS/rGO/Pt is reported along with its application, for the first time, as a catalyst for the photocatalytic reduction of carbon dioxide (CO₂) to methane (CH₄). TiO₂/CdS nanoparticles and Pt nanoparticle-decorated reduced graphene oxide sheets (rGO/Pt) were synthesized separately and characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, UV-vis spectroscopy and photoelectrochemical experiments. Hydrocarbon samples were collected and analysed using gas chromatography (GC). After 5 hours of illumination under visible light, 0.11 μmol of CH₄ was produced at an average production rate of 0.0867 μmol h⁻¹, which is higher than the production of CH₄ measured from the TiO₂/CdS and the TiO₂/CdS/Pt control samples. The photoelectrochemical experiments confirmed that the presence of rGO sheets in the nanocomposite enhanced the electrochemical and photocatalytic properties of the nanocomposite as a result of rapid electron transport and the inhibition of charge recombination.