Electrodeposition and modification of Pd-based thin films

Actually platinum is still the most common metal catalyst in both anode and cathode fuel cell reactions because of its excellent properties in the adsorption and dissociation of small organics molecules (SOMs). The use of other alcohols with larger molecular weights has been investigated during the years and the direct ethanol fuel cells (DEFCs) may represent an interesting and promising alternative technology for the mobile application. While the Pt or Pd metals are the actives sites for the C-C activation of the ethanol, the main rule of a second transition metal inside a multicomponent catalyst is to improve the formation of oxygenated species (OHads) that are critically for the rate determining step of reaction (rds) and consequently increasing the kinetic of reaction. At the same time the possibility to have an electronic back donation from the transition metal to the d-band of Pt /Pd can weaken the bond between the absorbed CO species and the metal itself. In this presentation we would like to present the recent results concerning the modification of Pd samples by a strong oxidative/reductive treatment named Electrochemical Milling and Faceting (ECMF) performed in collaboration with the CNR of Florence. The treatment will be introduced as a common way for the modification of the catalytic activity of a Pd sample against the ethanol oxidation reaction but it will also be presented as a simple and innovative electrochemical synthesis procedure to obtain dispersed metals nanoparticles from a Pd foil. The possibility to combine a second metal by an electrodeposition technique has been studied in collaboration with the Zangari group of research at the University of Virginia focusing on the growth of Pd-Co thin films by co-deposition