Electrocatalytic activity of Pt-ZrO2 supported on different carbon materials for methanol oxidation in H2SO4 solution

Different carbon supports are considered to prepare Pt-ZrO2/XC-72R carbon black, Pt -ZrO2/SWCNTs and Pt-ZrO2/MWCNTs electrocatalysts by a solid-state reaction under intermittent microwave heating method using ethylene glycol and NaBH4 as mixed reducing agents. The prepared electrocatalysts are physically characterized using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM). Pt particle size decreases in the order: Pt-ZrO2/C > Pt-ZrO2/MWCNTs > Pt -ZrO2/SWCNTs. Cyclic voltammetry, chronoamperometry, chronopotentiometry and electrochemical impedance spectroscopy are applied to investigate the electrochemical performance of the three electrocatalysts for methanol oxidation in H2SO4 solution. CNTs supported electrocatalysts achieve increased methanol oxidation current density and improved stability behaviour during long-time operation when compared to the one containing carbon black. Pt-ZrO2/CNTs electrocatalyst also displays lower resistance and higher electrolyte diffusion rate to infer a faster charge transfer process and better electrode accessibility for methanol oxidation. Therefore, carbon nanotubes are suggested as ideal anode electrocatalyst supporting material for the practical application of direct methanol fuel cells. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.