Noble metals ordered intermetallic nanoparticles development and the study of the electrochemical activity for organic fuels and hydrogen oxidation reactions

Abstract

It urges the global demand for devices able to generate electric power in a sustainable development concept. Fuel cells are perfectly adjusted to such a situation considering that they are capable to produce energy from renewable fuels with a very low polluting characteristic. However, in order to achieve the wide application of these devices within an acceptable level of costs and performance it is necessary to develop and improve electrode materials to accomplish the chemical-energy conversion in an enhanced way, i.e. low susceptibility for surface poisoning by reaction intermediates and co-products and lower production cost as compared to the electrode materials commercially available nowadays. The special class of alloys, named ordered intermetallic materials, are been presenting as an interesting tool to develop the theory of electrocatalysis as well as promising electrode materials to be used in the actual devices. The higher physical-chemical stability of these materials allied to their homogeneous and well defined structure allows the experimental and theoretical studies to be extended to the nanoparticle form. This Project proposes the development of electrode materials as ordered intermetallic nanoparticles of noble metals (Pt, Au and Pd) and transition metals (Sb, Sn, Bi, Mo and others), the evaluation of the materials as anode for ethyleneglycol, glycerol and hydrogen oxidation reactions and the adsorption and oxidation processes of carbon monoxide in alkaline medium. Concomitantly to the experimental essays, theoretical studies of the adsorption step of reactant molecules and some selected intermediates at choose intermetallic surfaces will be performed to reach a better understanding of the influence of the surface structure in the reactions. Nanoparticles will be synthesized through the reduction polyol method of the respective metallic ions in tetraethyleneglycol medium. The synthesized products will be characterized by using R-ray diffraction, Scanning Electron Microcopy and X-Ray Energy Dispersed Spectrometry and Transmission Electron Microscopy techniques. After the physical characterization, the materials will be applied on glassy carbon surfaces as a thin active layer to be electrochemically evaluated as anode for the oxidation reaction of the fuels in 0.2M KOH solution. The electrochemical activities of the materials will be evaluated by cyclic voltammetry, chronoamperometry, rotating disc electrode and in situ infra-red spectroscopy prcedures. The studies will be complemented by the HPLC analysis of the electrolytes in order to determine stable intermediates and products of the organic fuels oxidation reactions. The whole set of collected information will support the understanding of the structural and electronic characteristics of the ordered intermetallic materials in ethyleneglycol, glycerol and hydrogen oxidation reaction in alkaline medium. (AU)