Influence of the preparation method and the support on H2O2 electrogeneration using cerium oxide nanoparticles

This work describes the influence of the preparation method and the carbon support using a low content of cerium oxide nanoparticles (CeO2/C 4%) on H2O2 electrogeneration via the oxygen reduction reaction (ORR). For this purpose, the polymeric precursor (PPM) and sol-gel (SGM) methods with Vulcan XC 72R (V) and Printex L6 (P) supports were employed. The materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The XRD analysis identified two phases comprising CeO2 and CeO2,. The smallest mean crystallite size was exhibited for the 4% CeO2/C_PPM_P material, which was estimated using the Debye-Scherrer equation to be 6 nm and 4 nm for the CeO2 and the CeO2, phases, respectively, and was determined by TEM to be 5.9 nm. XPS analysis was utilized to compare the oxygen content of the 4% CeO2/C_PPM_P to Printex L6. The electrochemical analysis was accomplished using a rotating ring-disk electrode. The results showed that the 4% CeO2/C specimen, prepared by PPM and supported on Printex L6, was the best electrocatalyst for H2O2 production in 1 mol L-1 NaOH. This material showed the highest ring current, producing 88% H2O2 and transferring 2.2 electrons per 02 molecule via the ORR at the lowest onset potential. Additionally, the ring-current of the 4% CeO2/C_PPM_P material was higher than that of Vulcan XC 72R and Printex L6, the reference materials for H2O2 production, indicating the highest electrocatalytic activity for the 4% CeO2/C_PPM_P material. (C) 2013 Elsevier Ltd. All rights reserved.