Geração de H2 a partir do etanol : efeito da adição de terras raras (La2O3, CeO2) e Pt nas propriedades atalíticas de Co/Al2O3 para reforma do etanol

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Ni or Co catalysts supported on Al2O3, La2O3-Al2O3 and CeO2-Al2O3 were prepared by impregnation of Al2O3 with an aqueous solution of lanthanum nitrate or ceria, followed by a calcination and incipient wetness impregnation with an aqueous solution of nickel or cobalt nitrate and promoted with Ag or Pt. The catalysts were characterized by temperature-programmed reduction (TPR), specific surface area, X-ray diffraction, temperature-programmed oxidation, Fourier transform infrared spectroscopy (FTIR), transmission electronic microscopy , scanning electron micrographs and X-ray absorption near edge structure (XANES). The results of TPR and XANES show the Co reduction occurring in two stages being the Co3O4 reduced to CoO and then to Co0. The Pt promotes the first stage of reduction. For FTIR of adsorbed CO, a change in the morphology of the catalyst when promoted with Pt or La2O3 was observed. The catalysts in steam reform of ethanol show high deactivation, independent of the used support, with carbon polymeric formation. With oxygen addition the reagents ethanol and water carbon deposition was suppressed. The La2O3 addition resulted in more stable catalysts, possibly due to suppression of the diffusion of Co ion to the structure of alumina, however, the carbon formation was not suppressed. With the addition of CeO2 a stable catalyst was obtained, suppressing the diffusion of the Co and the carbon deposition, which was due to high mobility of the oxygen of CeO2 to the Co surface and oxidation of the carbon formed.

ASSUNTO(S)

co/ceo2-al2o3 catalisadores engenharia quimica hidrogênio cinética química Álcool

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