Evaporation-induced self-assembly of mesoporous zirconium silicates with tunable acidity and facile catalytic dehydration activity

摘要

Zirconium ions were incorporated into mesostructured silicate by evaporation-induced self-assembly (EISA) method without the addition of a mineral acid. Zr loadings up to 26.5 wt% were achieved. The BET surface area and the pore volume of the Zr-EISA samples are in the range of 818-614 m(2)/g and 1.2-1.01 cm(3)/g, respectively. Amorphous ordered pore structure was evident from HR-TEM images. Diffuse reflectance UV-Vis spectra reveal that a majority of the Zr exists as isolated framework species and impart Lewis acidity. Pyridine FTIR analysis revealed the presence of both Lewis and Bronsted acid sites in the Zr-EISA samples. The Zr-EISA materials exhibit excellent isopropanol dehydration activity with nearly total olefin selectivity characterized by a moderate activation energy (approximately 86 +/- 1 kJ/mol). (C) 2015 Elsevier Inc. All rights reserved.