Electrocatalytic activity of Pd-Au nanoalloys during methanol oxidation reaction

Methanol fuel cells are very promising power source due to its high efficiency and low emissions of pollutants but their commercialization is hindered by development of the effective catalysts. Bimetallic nanostructured catalysts have been used to increase the effectiveness of methanol electrooxidation. Their high electrocatalytic activity can be accounted largely by the difference in electronegativity of two metals (e.g. Pd and Au), that resulting in gradual Au delta+ -> Au delta- transition with the increase in Pd content. Therefore, gold enriched bimetallic Pd-Au-nano were recommended as catalysts for oxidation processes since they are characterized by the presence of Au delta+ on their surface. Deposition of Pd, Au and Pd-Au nanoparticles (similar to 50-350 nm) were carried out in dimethyl sulfoxide by pulsed mode of electrolysis directly on electrode surface. Cyclic voltammetry was the main method to study catalytic properties of the modified electrode in the anode oxidation process of methanol. It was found that oxidation rate on the electrode surface modified by Bimetallic nanoalloy bimetallic Pd-Au nanoparticles is similar to 1.5 times higher as compared to that in the case of electrodes modified by Pd or Au monometallic nanoparticles individually. In order to find highly active, selective, and stable catalysts for methanol electrocatalytic oxidation reaction additional studies are needed to understand the role of electrode surface charge and local OH- ions concentration from alkali solution. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.