Studies of the influence of metal-support interaction on the mechanism of the ethanol oxidation reaction on Pd nanoparticles

Abstract

This project intends to carry out comparative and systematic studies of the ethanol oxidation reaction in alkaline medium on Pd nanoparticles on hybrid supports containing carbon and transition metal oxides (SnO2/Sb2O5 e TiO2) with the purpose of elucidating the influence of metal-support interactions on the reaction mechanism. These interactions usually promote variations of the metal´s electronic properties, which in turn, can significantly modify the adsorption energies of ethanol as well as those of reaction intermediates and products. Thus, the electronic characteristics of Pd -the component that provides the reaction sites- can affect the rate of several steps of the reaction mechanism involving adsorbed species modifying the distribution of the reaction products. This proposal involves the use of hybrid supports with different amounts of oxides (from 10 to 50 wt.%), variations in the nanostructure of catalysts (Pd/C-óxido vs. Pd/óxido/C) and studies of the electronic occupancy of the Pd 4d band by X-ray absorption spectroscopy (XAS), as well as evaluating the effects of metal-support interactions on the Pd 3d binding energy by X-ray photoelectron spectroscopy (XPS). These studies will be combined with the assessment of catalytic activity by electrochemical techniques (cyclic voltammetry and chronoamperometry) and of the product´s distribution by spectroscopic techniques (FTIR), aiming to contribute to the development of new multifunctional catalysts for alkaline fuel cell anodes seeking energy generation using ethanol as fuel.