Eletrocatalisadores de platina promovidos com NiO aplicados na reação de oxidação de biocombustíveis.

Abstract

Renewable energy is key to supplying new technologies, and a promising alternative to generate clean energy would be the fuel cell (CF), which produces electricity with reduction of pollutants, and with the use of biomass fuels, it becomes a sustainable source of energy. However, it is necessary to minimize the cost of production and to facilitate the supply of CFs to enable the large-scale application. In this context, catalysts composed of Pt and NiO were prepared, which were characterized by X-ray Diffraction, Dispersive Energy Spectroscopy and Scanning Electron Microscopy. The catalysts had a cracked-mud look, homogeneous distribution on the surface and concentrations close to the nominal ones. A direct relationship between crystallite size and Pt concentration was also observed. In addition, there was no alloying between Ni and Pt, since no changes were detected in platinum network parameters (cfc). The characterization of the electrocatalytic behavior of glycerol oxidation in PtxNi(1-x)Oy/Ti electrodes was investigated in alkaline medium. The catalysts were prepared by thermal decomposition of polymer precursors in different metal compositions with high electrochemical surface area. The results of cyclic voltammetry and chronoamperometry showed that glycerol oxidation current densities for mixed electrodes were higher than those obtained for electrodes containing only Pt at low potential values. In addition, the change in the onset potential of glycerol oxidation towards less positive values was also recorded, showing a facilitated oxidation with these materials compared to Pt. The electrodes that stand out are Pt0.8Ni0.2Oy/Ti and Pt0.9Ni0.1Oy/Ti because they have the highest electroactivity and the highest efficiency, respectively.