Characterization and electrochemical properties of Carbon/CeO2 composites prepared using a hydrothermal method

Abstract

The electrochemical performance of carbon was improved by forming composites with CeO2 nanoparticles as an electrode material for supercapacitor applications. The carbon/CeO2 composites were prepared using a hydrothermal treatment with polyvinylpyrrolidone (PVP) referred to as carbon/CeO2-PVP or sodium hydroxide (NaOH) referred to as carbon/CeO2–NaOH. CeO2-PVP and CeO2–NaOH nanoparticles with no carbon composite were also prepared for comparison. All samples were characterized using X-ray diffraction (XRD), Raman spectroscopy (Raman), field emission scanning electron microscope, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), the Brunauer-Emmett-Teller and a potentiostat/galvanostat electrochemical cell system. XRD, Raman and TEM results confirmed the formation of a composite between carbon and CeO2 nanoparticles. XPS measurements of Ce ions in the samples indicated Ce3+ and Ce4+. Specific capacitances at a current density of 0.25 A/g were 64.1, 123.8 and 139.2 F/g for electrodes made from carbon, carbon/CeO2-PVP and carbon/CeO2–NaOH, respectively. Capacitance values of these composites were higher than that of carbon due to the contribution of the redox reaction of Ce3+/Ce4+ within the CeO2 nanoparticles.