文献类型：期刊文献

英文题名：Direct synthesis of Cr-MCM-48-like large pore mesoporous silica

作者：Wang, Lingzhi[1]; Wang, Lei[1]; Zhang, Jinlong[1]

机构：[1] Lab for Advanced Materials, Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China

年份：2009

卷号：44

期号：24

起止页码：6512

外文期刊名：Journal of Materials Science

收录：EI(收录号：20095212570198)

语种：英文

外文关键词：Pore size - Paramagnetic resonance - Electron spin resonance spectroscopy - Silica - Mesoporous materials

摘要：Chromium-substituted MCM-48-like large pore mesoporous silica with average pore size up to 10 nm was directly synthesized by using P123 (EO 20PO70EO20) as a template, n-butanol as an assistant, and chromic nitrate nonahydrate as a chromium source. The Cr species was doped by simply adjusting the pH of the synthesis system with ammonia from strong acid to nearly neutral after crystallization for 24 h. The Si/Cr ratios in the initial gel ranged from 10 to 80, and the actual weight percentage of Cr was analyzed by ICP. XRD pattern, high-resolution TEM, and N2 adsorption-desorption isotherm were employed to investigate the pore structure properties of these materials. The results showed that all the samples had Ia3d cubic structure and the pore channels were highly ordered. UV-vis, wide-angle XRD, and ESR spectra revealed that at lower Cr content (Si/Cr > 30), only Cr (VI) and Cr(V) species existed in the mesoporous framework, and at higher Cr content, Cr (III) species appeared. ? 2009 Springer Science+Business Media, LLC.