A. Oliveira Neto

Synthesis of electrocatalysts by the Bönnemann method for the oxidation of methanol and the mixture H2/CO in a Proton Exchange Membrane Fuel Cell

The synthesis of ternary electrocatalysts Pt/Ru/Mo type were performed according to the Bonnemann method and characterized by the following techniques: energy dispersive analysis (EDX), X-rays diffraction (XRD), cyclic voltammetry (CV) and polarization curves (E vs. i) for the oxidation of H2, H2/CO and methanol in a Proton Exchange Membrane Fuel Cell (PEMFC). Catalysts structure consists of highly dispersed nanocrystals in carbon support, with an average particle size of 2 nm. The results of cyclic voltammetry suggest an enhancement of the catalyst electroactivity with the addition of cocatalysts. Polarization curves indicate that Pt/Ru/Mo systems could be employed as electrode material for PEM fuel cell for technological application.

Eletro-oxidação de etanol sobre eletrocatalisadores PtRh/C, PtSn/C e PtSnRh/C preparados pelo método da redução por álcool

PtRh/C, PtSn/C and PtSnRh/C electrocatalysts were prepared by the alcohol-reduction process and characterized by EDX, XRD and cyclic voltammetry. The electro-oxidation of ethanol was studied by cyclic voltammetry using the thin porous coating technique. In the region of interest for direct ethanol fuel cell (0.3-0.4V) PtSn/C and PtSnRh/C eletrocatalysts were more active than PtRh/C electrocatalysts.

Oxidação eletroquímica do metanol sobre partículas de PtRu e PtMo suportadas em carbono de alta área superficial

The electro-oxidation of methanol was studied on Pt/C, PtRu/C and PtMo/C. These catalysts were prepared by the formic acid method developed in this laboratory. The products of methanol oxidation were monitored by DEMS experiments. The activity of the catalysts for the oxidation of methanol was studied by cyclic voltametry and cronamperometry.

Ethanol Electrooxidation on Pt with Lanthanum Oxide as Cocatalyst in a DAFC

Electrocatalytic activity toward ethanol electrooxidation of Pt particles in PtLa/C catalysts with different Pt : La ratios has been studied with different electrochemical and spectroscopic techniques, and the results were compared to those of Pt/C catalyst. Significant enhancement in the electrocatalytic activity has been achieved by depositing the Pt particles with lanthanum oxides/hydroxides using an alcohol reduction method. Compared to Pt/C catalyst, PtLa/C materials exhibit a lower onset potential and a higher electron-transfer rate constant for the investigated reaction. These studies illustrate the possibility of utilizing Pt/C with La oxides/hidroxides as electrocatalyst for direct alcohol fuel cells (DAFCs).