ESR and ESEM studies of Mn-containing MCM-41 materials

被引：59

作者：

Xu, J ^{[1
]}

Luan, ZH ^{[1
]}

Wasowicz, T ^{[1
]}

Kevan, L ^{[1
]}

机构：

[1] Univ Houston, Dept Chem, Houston, TX 77204 USA

来源：

MICROPOROUS AND MESOPOROUS MATERIALS | 1998年 / 22卷 / 1-3期

基金：

美国国家科学基金会;

关键词：

manganese ion; electron spin resonance; MCM-41; electron spin echo;

D O I：

10.1016/S1387-1811(98)00103-6

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

Through electron spin resonance (ESR) and electron spin echo modulation (ESEM) studies, three Mn(II) species are found in three kinds of Mn-containing MCM-41 materials: ion-exchanged Mn-MCM-41, synthesized MnMCM-41 and synthesized MnMCM-41(Ca) with subsequent CaCl(2) exchange. Mn(II) species I with a well-resolved sextet centered at g= 2.007 has distorted octahedral symmetry and is observed in hydrated ion-exchanged Mn-MCM-41 and in synthesized calcined MnMCM-41. Mn(II) species II with g= 5.2 and 3.2 is observed in dehydrated Mn-MCM-41 and MnMCM-41; attributed to zero field interactions. Both species I and II correspond to extra-framework Mn(II). Mn(II) species III, with a symmetric line at g= 2.004 and a broad line-width of 250 to 350 G is assigned to framework sites. Extra-framework Mn(II) species I and II coordinate with four D(2)O and are accessible to water, but framework Mn(II) species III coordinates with only three D(2)O and is less accessible to water. (C) 1998 Elsevier Science B.V. All rights reserved.

引用

页码：179 / 191

页数：13

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