Electrochemical Preparation, Characterization of Molybdenum-Oxide/Platinum Binary Catalysts and Its Application to Oxygen Reduction Reaction in Weakly Acidic Medium

Abstract

This study reports a detailed analysis of an electrode material containing molybdenum oxide and platinum nanoparticles which shows superior catalytic effect towards to oxygen reduction in weakly acid medium. The material is sequentially electrodeposited on a glassy carbon electrode from aqueous solutions of MoO42− and PtCl42− either by cycling the potential or by applying pulsed potential technique. Chemical and morphological characterization of the electrode surface was made by X-ray photoelectron spectroscopy, scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The electrode performance towards oxygen reduction reaction was investigated in pH 5.0 acetate buffer solution saturated with oxygen and parameters such as the cell content and electrodeposition conditions were optimized. The performance of the electrode was compared with Pt disk, bare glassy carbon, platinum modified glassy carbon electrodes along with the electrode modified in a single step and named as Pt-MoOx/GCE. Overall results indicated that sequentially deposited molybdenum oxide and platinum modified glassy carbon electrode designated as Pt/MoOx/GCE has shown higher catalytic activity considering the peak location and current intensities. This was consisted with the pulsed electrodeposition process and even higher catalytic activity was obtained than the electrode modified by cycling voltammetry.