Promoting Effect of Gd 2 O 3 in Pt-Gd 2 O 3 /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, Gd 2 O 3 prepared by simple precipitation method (Gd 2 O 3 (PC)) and polymer-assisted method (Gd 2 O 3 (PL)) is examined as support for Pt/C. The Gd 2 O 3 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 Gd 2 O 3 (PC) for MOR activity. The microwave-assisted polyol reflux method is used to prepare Pt-Gd 2 O 3 (PC)/C and Pt-Gd 2 O 3 (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-Gd 2 O 3 (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/Gd 2 O 3 to adsorbed CO. This electron transfer reduces the Gibbs free energy for CO adsorption and decreases the CO poisoning. The overall benefit of Gd 2 O 3 is to increase the performance of Pt electrocatalyst for methanol oxidation.