各类介孔分子筛

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介孔分子筛
Mesoporous Materials
1、什么是介孔分子筛？
国际纯粹和应用化学协会（IUPAC）的定义：
介孔材料就是孔径在 2-50 nm 的材料，
介孔就是介于微孔和大孔之间。

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3＜2nm 2-50nm
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1992 年，Mobil 的科学家们（Kresge等）
制备出孔道均匀、孔径可调的介孔M41S，
该材料包括： MCM-41；
MCM–48；
MCM-50；
MCM 为 Mobil 公司合成的孔材料的系列名称， M obil C omposite of M atter-美孚合成的物质
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molecular sieves science and technology
Synthesis Vol.1 1998
Springer
The Synthesis and Properties of M41S and Related Mesoporous Materials
C.T.Kresge
分子筛与多孔材料化学-徐如人
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MCM-41
MCM –41 exhibits an X-ray diffraction pattern (XRD)
containing three or more low angle peaks (below 10° 2θ)
that can be indexed to an hexagonal hk0 lattice
This particular sample has a unit cell of approximately 46 Å
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透射电镜 transmission electron micrograph (TEM) the uniform honey-comb like structure
Lattice Image MCM-41
Possible Structure MCM-41属于六方相
含有规则的二维孔道阵列,
MCM-41
用不同尺寸的表面活性剂分子作为模板剂，
孔道的尺寸可在1.5-10nm之间变化
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MCM-48
The X-ray diffraction pattern consists of several peaks that can be assigned to the Ia3d space group.
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MCM-48
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MCM-48
The structure of MCM –48 has been proposed to be bicontinuous with a simplified representation of two infinite three-dimensional,mutually intertwined, unconnected networks of rods as initially
proposed by Luzzatti
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MCM-50
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19MCM-50
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2、介孔分子筛分类
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The M41S family
hexagonal unit cell
MCM–41 (two dimensional, p6m),
cubic structures
MCM–48 (three dimensional, Ia3d)
lamellar structures
MCM–50 which is a post-stabilized lamellar material.
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FSM-16 ：
使用与M41S家族相同的模板剂
用层状kanimite 为原料制备
与 MCM-41 结构相似
FSM代表F olded S heets M esoporous Material
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1995
在中性条件下，以伯胺为模板剂，
依靠氢键相互作用，
合成出规则孔道，孔壁较厚的HMS；
用可生物降解的非离子表面活性剂为模板剂，在中性条件下，合成了MSU
HMS 代表H exagonal M esoporous S ilica；
MSU 代表M ichigan S tate U niversity material
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突破了只依靠正负电荷的相互作用合成介孔分子筛的方法，
把氢键作用的思维引入到介孔分子筛合成
使介孔分子筛的合成思路得到拓宽。

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SBA-1，SBA-2, SBA-3
霍启升用双子铵类双亲性物资为模板剂，
在强酸性体系中合成出 SBA-1，SBA-2, SBA-3
hexagonal unit cell
SBA–2 (three dimensional, p63/mmc),
SBA–3 (two dimensional p6m
structure similar to MCM–41 but synthesized in an acid media;
cubic structures
SBA–1 (Pm3n);
分子筛的有序度要好很多，骨架上具有笼型结构
SBA 代表 University of California,
S anta Ba rbara
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SBA-15介孔分子筛
赵东元等
以三嵌段高分子聚合物（PEO-PPO-PEO）为模板剂，
在强酸体系下合成，
高度有序、
大孔间距、
纯硅
二维六方孔道
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31 1. 介孔材料的诞生－－1992年MS41系列分子筛(典型的是MCM-41,MCM-48,MCM-50)的合成：
Nature. 1992, 359, 710-712（J. S. Beck ）
J Am Chem Soc. 1992, 114: 10834-10843（J. S. Beck ）
Science. 1993, 261: 1299-1303(霍启升）
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2.介孔材料制备的另一里程碑－－1998年赵东元合成了SBA-15
Science. 1998, 279: 548-552（赵东元）
J. Am. Chem. Soc. 1998, 120, 6024-6036 （赵东元）
3、介孔分子筛的合成及机理
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介孔孔径可以在5～50 nm 范围内变化,
且孔壁较厚(典型的在3 到9 nm) ,
该材料具有更高的热和水热稳定性。

其中的模板剂可通过焙烧或溶剂萃取脱除,
且焙烧温度要比MCM-41 低得多
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41合成机理
Beck et al
templating (LCT) mechanism.
They proposed that the structure is defined by the organization of surfactant molecules into liquid crystals表面活性剂组装成液晶
which serve as templates for the formation of the MCM-41 structure.作为合成的模板剂
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the first step in the synthesis would correspond to the formation of a micellar rod around the surfactant micelle
表面活性剂分子首先形成棒状胶束
which in a second step will produce a hexagonal array of rods,形成六方棒的阵列
followed by incorporation of an inorganic array (silica, silica-alumina) around the rodlike structures.围绕棒状胶束结构,无机物形成阵列
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the liquid crystal structures formed in surfactant solutions are highly sensitive to the overall characteristics of the solution,
液晶的形成对于溶液的性质非常敏感
only in the cases where the surfactant and synthesis conditions allow the formation of well-defined liquid crystal hexagonal structures, 只有表面活性剂分子形成良好的六方液晶结构，才能合成出MCM-41
is the synthesis of MCM-41 successful.
when C6 and C8 alkyl chain surfactants were used, MCM-41 was not formed,
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