Abstract

PICASSO, Gino et al. Preparation of catalysts based on Ce-Mn mixed oxide by coprecipitation for combustion of n-hexane. Rev. Soc. Quím. Perú [online]. 2013, vol.79, n.4, pp.367-380. ISSN 1810-634X.

Catalysts based on Ce-Mn mixed with different Ce/Mn molar ratios ranging from 0,5 to 2 have been prepared by coprecipitation at pH constant with ageing times of 4, 18 and 24 h for combustion of n-hexane. XRD patterns of the mixed oxides showed the majority presence of fluorite phase. Specific BET surface areas of mixed oxides were always higher than their single counterparts and their adsorption isotherm depicted a mesoporous surface of Type IV. TPR thermograms confirmed the presence of mixed oxide phase, whose profile shifted to smaller temperatures with increasing content of ceria. Catalytic tests were performed with 2000 ppm of n-hexane and WHSV of 80 h^-1 in a fixed-bed reactor. For all samples, only CO₂ and water were observed at total conversion and no partial combustion products were obtained. Ce-Mn mixed oxides were more active than simple oxide samples no matter the aging time. Mixed samples presented thermal stability in contrast with simple ones. Mixed sample with Ce/Mn molar ratio of 2 depicted the highest activity probably due to higher surface area and better reducibility ability of mixed phase.

Keywords : n-hexane; mixed oxides; Ce-Mn.

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