Synthesis and catalytic application in isobutane dehydrogenation of the mesoporous chromia/alumina catalysts based on a metal-organic framework

The mesoporous chromia/alumina (Cr2O3/Al2O3) catalysts were successfully synthesized using a porous metal-organic framework MIL-101 (Cr3F(H2O)(2)O(BDC)(3)center dot nH(2)O, BDC = 1,4-benzenedicarboxylate) as a molecular host and chromium precursor, inorganic aluminium salt as the aluminium precursor. The aluminium sources had the significant effects on the structure of the products. The formation of alpha-Cr2O3 phase was observed in the mesoporous catalyst (Cr2O3/Al2O3-C) prepared by AlCl3 center dot 6H(2)O, whereas additional chromia alumina solid solution CrxAl2-xO3 phase was produced in the catalyst (Cr2O3/Al2O3-N) using Al(NO3)(3)center dot 9H(2)O as the aluminium precursor. The surface Cr species existed in the Cr6+ and Cr3+ state over the mesoporous catalysts. The Cr species had a strong interaction with the alumina support. Preliminary catalytic studies showed that the Cr2O3/Al2O3-N catalyst exhibited much higher isobutene selectivity and higher stability than the reference catalyst in the isobutane dehydrogenation. The maintainable dehydrogenation activity during the five dehydrogenation-regeneration cycles indicated high regenerative ability of the catalyst Cr2O3/Al2O3-N. Consequently, this study represents a feasible way toward the facile synthesis of the mesoporous chromia/alumina catalyst. Moreover, this work proposes a novel application of metal-organic framework

One-pot synthesis of ordered mesoporous zirconium oxophosphate with high thermostability and acidic properties

A series of mesoporous zirconium oxophosphate (M-ZrPO) with different P/Zr molar ratios (0-1.25) has been prepared via a facile one-pot evaporation-induced self-assembly (EISA) strategy. After removing the structure-directing agents, the M-ZrPO with large specific surface area (160 m(2) g(-1)), big pore volume (0.26 cm(3) g(-1)) and narrow pore size distribution (5.64 nm) has been obtained. Small-angle X-ray diffraction (SXRD) and transmission electron microscopy (TEM) results showed that these materials had ordered mesoporous structure. With the increase of P/Zr, the textural properties of M-ZrPO could be improved. Moreover, the ordered mesostructure could be maintained even when treated at 800 degrees C, indicating the M-ZrPO had attractive thermal stability. NH3-TPD and pyridine-IR analyses showed the presence of abundant Bronsted and Lewis acid sites in the material. The M-ZrPO has been used successfully as solid acid catalyst and showed excellent performance in the ketalization reaction