Resumo

DAZA, Carlos Enrique; MONDRAGON, Fanor; MORENO, Sonia  e  MOLINA, Rafael. CO2 reforming of methane over Ni-Mg-Al-Ce mixed oxides derived from hydrotalcites: Mg/Ni ratio effect. Rev.fac.ing.univ. Antioquia [online]. 2011, n.57, pp.66-74. ISSN 0120-6230.

Ni-Ce/Mg-Al catalysts were obtained by means of the hydrotalcite reconstruction method in the presence of [Ce(EDTA)]^- complex. The effect of the Mg/Ni ratio was studied when the mixed oxide was reconstructed with 3 wt. % Ce loadings. The materials were characterized by X-Ray Diffraction (XRD), Thermal-Gravimetric Analysis (TGA), Temperature-Programmed Reduction (TPR-H₂), Temperature-Programmed Oxidation (TPO) and CO₂ Temperature-Programmed Desorption (TPD-CO₂). The reduced catalysts were tested in CO₂ reforming of methane under two operation regimens: i) reaction between 500 to 800°C using volumetric ratios of CH₄/CO₂/ Ar=5/5/40 and, ii) isothermal reaction at 700°C using volumetric ratios of CH₄/CO₂=18/22 without diluent gas. The solids showed strong basic characteristics and high Ni-surface interactions which determined their catalytic performance. Catalysts with Mg/Ni molar ratios of 2 and 4 showed high CH₄ and CO₂ conversions with H₂/CO molar ratios between 0.7 and 1.1 without coke formation under severe isothermal reaction conditions. The yields and activities were higher when reduction increased.

Palavras-chave : Hydrotalcite; cerium; reforming; methane; syngas.

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