Eletro-oxidação de metanol e etanol sobre catalisadores suportados de 'PD''AU'

• Ano de defesa: 2015
• Autor(a) principal: Abreu, Thiago Holanda de [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Físico-química; Eletrocatálise; Células à combustível; Eletroquimica; Nanopartículas; Nanoparticles
• Link de acesso: http://hdl.handle.net/11449/124432

The development of electrocatalysts for the oxidation of alcohols like methanol and ethanol is of great importance, once such alcohols can be used as fuel at the anode of fuel cells, devices that convert chemical energy into electrical energy. Thus, this work reports the synthesis of nanocatalysts of PdAu supported on carbon, physical characterization of materials prepared and the evaluation of the catalytic activity for the oxidation of methanol and ethanol. The physical characterization was performed using X-ray diffraction, transmission electron microscopy, Energy Dispersive spectroscopy X-Ray and X Ray Absorption Spectroscopy techniques. Materials were also electrochemically characterized by cyclic voltammetry. The catalytic activity of the prepared materials was studied using standard electrochemical techniques such as chronoamperometry and cyclic voltammetry and also the spectroelectrochemical technique of in situ FTIR, which allows the identification of reaction products and intermediates. With the X-ray diffraction was possible to prove the gold incorporation into the Pd structure for some materials. The transmission electron microscopy images showed a widening in the distribution of particle size with increasing the amount gold in the material, and a good dispersion of the nanoparticles on carbon support, except for pure Pd. The X-ray absorption spectra indicated a emptying on the 4d band of the material containing PdAu. Related to the catalytic activity for the electro-oxidation of ethanol and methanol, materials containing both palladium and gold showed better activity than pure Pd. The spectro-electrochemical data indicate acetate as main oxidation product for ethanol oxidation and formate for methanol oxidation.