Authors: Cristina Locatelli Alessandro Minguzzi Alberto Vertova Sandra Rondinini
Publish Date: 2013/01/04
Volume: 43, Issue: 2, Pages: 171-179
Abstract
In this work SnO2 + IrO2 mixed oxides are studied as electrocatalysts for the oxygen reduction reaction ORR in alkaline media by means of voltammetric techniques under controlled mass transfer conditions thanks to the use of rotating ring disk electrodes RDE/RRDE The oxides prepared by sol–gel methodology are supported on the disk electrodes using a thin layer of anionic exchange polymer as gluing agent The amount of deposited polymer was optimized to avoid any limitation due to the diffusion of reactant/products across the film thickness The mixed oxides were prepared at the following mole fractions of IrO2 x textIrO 2 = 015 031 055 073 and 1 The role of composition was studied in terms of the reaction pathways and the relevant fraction of H2O2 production together with the potentials of the onset of ORR The fraction of sites able to give proton/hydroxyl and electron transfers is also determined and discussed The results point to the best performance of lowIr containing mixtures and to their low sensitivity to the presence of methanol a key feature in the case of crossover in alkaline direct alcohol fuel cells
Keywords: