Synthesis and physico-chemical characterization of ceo 2/zro 2-so 42-mixed oxides

Abstract

Environmentally friendly solid-acid catalysts CeO 2/ZrO 2-SO 42- were prepared by the sol gel method varying CeO 2 content (10, 20 and 30 wt%) and using sulfation in situ, maintaining the sulfate ions amount present in the materials at 20 wt%. ZrO 2 and ZrO 2-SO 42-were also prepared for comparison proposes using the same synthesis method. The materials were characterized by X-ray diffraction, nitrogen physisorption, potentiometric titration with n-butylamine, decomposition of 2-propanol and n-pentane isomerization. The specific surface area of ZrO 2-SO 42- was high (160 m 2/g) compared with the unmodified ZrO 2 (80 m 2/g), however this area decreased with increasing the CeO 2 content (37-100 m 2/g). There was no significant effect of CeO 2 on the tetragonal structure of ZrO 2-SO 42-. The variation of acid sites amount runs parallel to the change of specific surface area. The acid sites amount decreased with increasing cerium oxide content. The decomposition of 2-propanol results fundamentally in the formation of dehydration products such as propylene and diisopropyl ether, both involving acid sites. In addition, a good performance during the n-pentane isomerization was observed for these materials. The selectivity towards isopentane reaches 84% when the Pt/CeO 2/ZrO 2-SO 42- catalyst with the highest CeO 2 content was used. © 2012, Sociedad Química de México.