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Indexed by:期刊论文

Date of Publication:2007-04-03

Journal:CHEMISTRY OF MATERIALS

Included Journals:SCIE、EI

Volume:19

Issue:7

Page Number:1664-1670

ISSN No.:0897-4756

Abstract:Novel Ti-containing mesoporous materials with wormhole structure (Ti-WMS) can be assembled from preformed titanosilicate-1 precursors with long-chain alkylamines as structure directors. The obtained products were characterized by a series of techniques including powder X-ray diffraction, transmission electron microscopy, FT-infrared spectroscopy, UV-visible spectroscopy, N-2 sorption, and hyperpolarized Xe-129 NMR at variable temperature. The catalytic properties of the materials were investigated by oxidative desulfurization reactions. The results show that Ti-WMS, whose synthesis utilizes zeolite precursors as total or part of the silica and titanium sources, is a pure mesoporous phase. However, the prepared materials contain additional micropores except the uniform mesopores, which is confirmed by N-2 sorption and Xe-129 NMR. Infrared spectra indicate that there are zeolitic primary and secondary building units in the pore walls of Ti-WMS. UV-visible spectroscopy results confirm the existence of active Ti4+ species. Ti-WMS is very active in the oxidation of bulky sulfides such as benzothiophene, dibenzothiophene, and 4,6-dimethyl dibenzothiophene, with activities similar to Ti-HMS. However, in thiophene oxidation, which is not diffusion-limited, Ti-WMS exhibits much higher catalytic activity than Ti-HMS because of the presence of micropores and zeolite-like active sites.