Palladium-Based Electroactive Materials for Environmental Catalysis

Abstract

A method has been proposed and justified to fabricate palladium-based electroactive materials by electrochemical dispersion of palladium under the action of a pulsed alternating current. The effect of the nature of the electrolyte on the composition and microstructural characteristics of palladium-containing catalysts has been studied by thermogravimetric analysis, UV-Vis spectroscopy, X-ray fluorescence analysis, X-ray powder diffraction analysis, and transmission electron microscopy. A set of the most probable chemical and electrochemical processes occurring under the action of pulsed alternating current and causing the formation of Pd and PdO nanoparticles has been considered. The effect of the synthesis parameters and the nature of the electrolyte on the activity of the obtained catalysts has been investigated. It has been shown that the electrocatalytic activity of Pd–PdO/C materials in the oxidation of ethanol in an alkaline medium is determined by the presence of an oxide phase in the catalyst composition and the size of palladium particles; this activity is maximum for materials with a slight predominance of PdO and with palladium particle sizes of more than 10 nm. For the oxidation of formic acid in an acid medium, catalysts with a minimum content of the oxide phase are more active, which is due to differences between the mechanisms of oxidation of formic acid and ethanol.