Nanomaterials Applied as Electrocatalysts in the Oxidation Reaction of Ethanol

Electrocatalyst containing platinum supported on high surface area carbon Vulcan XC-72 were synthesized by the method of reduction by alcohol and tested in comparison to ethanol oxidation reaction in acidic medium. The materials studied were Pt/C 20%, Pt80Ir20/C, Pt80W20/C, Pt80Sn30/C and Pt60Ir10Sn30/C using as a standard for comparison the commercial catalyst Pt/C 20% E-TEK. Physical characterization was performed using energy dispersive (EDX), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and electron microscopy X-ray scanning by high resolution field emission ("Field emission electron gun") (FEG-SEM). The EDX analysis showed that the theoretical compositions for synthesis are very close to the experimental values. From the results obtained by X-ray diffraction it was possible to calculate the average crystallite size and the lattice parameter of the samples studied. All materials showed a crystalline structure characteristic of face-centered cubic structure of platinum with the lattice parameter changes as a function of added metal. The analysis of SEM and TEM-EGF provided the particle size and the distribution and dispersion in the carbon support. The electrochemical results showed that the addition of different metals to platinum increased the catalytic activity of the electrocatalyst and among the evaluated materials the ternary one showed the best response under the conditions studied.