Methanol Oxidation in Alkaline Media with Pt-Au/fMWCNTs and Pt-Pd/fMWCNTs Electrocatalysts on an Exfoliated Graphite Electrode

Abstract

The poisoning of pure platinum electrodes has propelled the improvement of platinum-based alloy catalysts. In this work, we report the application of exfoliated graphite electrode as an anode platform for binary platinum-based electrocatalysts for methanol oxidation in alkaline media. Platinum-based binary electrocatalysts comprising of Pt-Au and Pt-Pd nanoparticles on functionalized multi-walled carbon nanotubes (MWCNTs) support were synthesized via polyol process. The nanocomposite electrocatalysts (Pt-Au/fMWCNTs and Pt-Pd/fMWCNTs) were characterized by transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffractometer (XRD). The electrochemical activity of the Pt-Pd/fMWCNTs and the Pt-Au/fMWCNTs electrocatalysts was assessed utilizing cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) in the presence of methanol. The nanoparticles were in the size regime of 3 to 5 nm and the XRD affirmed successful functionalization of the MWCNT and its impregnation with the binary Pt nanoparticles. The electrooxidation of methanol in alkaline conditions was seen with a high current density of about 26.1 mA cm−2 on Pt-Au/fMWCNTs and 13.52 mA cm−2 on Pt-Pd/fMWCNTs electrocatalysts deposited on exfoliated graphite working electrodes. The exfoliated graphite platform is a promising electrode for fuel cell application.