Electrochemical Properties of Gold-Palladium Core-Shell Nanostructures for Ethanol Oxidation

Gold-palladium nanoparticles (NPs) have been used as catalysts due to their catalytic activity, selectivity and stability for a variety of reactions, such as the small organic molecule oxidations (i.e. ethanol). In the present contribution, the catalytic activity of Pd and Au-Pd core-shell (CS) NPs is investigated towards the ethanol oxidation (Figures 1A and 1B). The Au-Pd CS NPs were synthesised by a seed-mediated growth method, where PdCl₄^2- is reduced at the surface of Au NPs in the presence of ascorbic acid. This method allows adjusting the average Pd shell thickness between 1 (CS1) and 10 (CS10) nm, by varying the amount of palladium chloride. Electrochemical studies in potassium hydroxide (KOH) containing electrolyte solutions with ethanol show that the current density of ethanol oxidation decreases as the shell thickness decreases. Correlation between catalytic activity and shell thickness will be discussed in terms of the structural parameters.