Promoting Effect of Gd2O3 in Pt-Gd2O3/C Electrocatalyst for Methanol Oxidation Reaction

Abstract

Metal oxides have been used as supports and promoters to enhance the electrocatalytic activity of Pt/C for methanol oxidation reaction (MOR). In this work, Gd2O3 prepared by simple precipitation method (Gd2O3(PC)) and polymer-assisted method (Gd2O3(PL)) is examined as support for Pt/C. The Gd2O3 samples are characterized by FTIR, HR-SEM, and PXRD. The ease of surface oxygen exchange and formation of surface –OH groups are better in the case of Gd2O3(PC) for MOR activity. The microwave-assisted polyol reflux method is used to prepare Pt-Gd2O3(PC)/C and Pt-Gd2O3(PL)/C) electrocatalysts. Electrocatalysts are characterized by XPS, ICP, TEM, PXRD, and examined by cyclic voltammetry (CV), CO stripping experiments, chronopotentiometry (CP), and chronoamperometry (CA) in acidic media. The MOR activity of Pt-Gd2O3(PC)/C is found to be 2.8 times higher than commercial Pt/C with good anti-poisoning activity. This result is further corroborated by the first principle calculations which show that there is significant electron transfer from Pt/Gd2O3 to adsorbed CO. This electron transfer reduces the Gibbs free energy for CO adsorption and decreases the CO poisoning. The overall benefit of Gd2O3 is to increase the performance of Pt electrocatalyst for methanol oxidation.