Mesoporous silica matrix

Since the discovery of ordered mesoporous silica materials such as MCM-41 [1] and FSM-16 [2], many attempts have been made to apply them for various type of catalysis [3]. Especially, much attention has been paid to the catalytic functions generated through the incorporation of heteroelements into mesoporous silica matrix, but not so much to those of mesoporous silica without heteroelements. This may be because silica itself is known to be inactive for many catalytic reactions. 

The EPR spectrum of the P-carotene cation radical (12) imbedded in a mesoporous silica matrix was recently reported [123],... 

In this paper, we present a simple and direct synthesis procedure for composite material consisting of ZSM-5 nanocrystals embedded in a mesoporous silica matrix. The samples were characterized and their catalytic activity evaluated using decane hydroconversion. 

Here we report on the first synthesis and characterization of nanostructured Cdi. Mn S within the mesoporous system of MCM-41 silica. Several characterization techniques (e.g. TEM, XRD, nitrogen physisorption, x-ray absorption and PLE spectroscopy have been applied to show the preservation of the pore structure as well as to investigate the structure and physical properties of the included diluted magnetic semiconducting guest species. The obtained results reveal a coating of the iimer surface of the mesoporous silica matrix by CdS which is almost statistically doped with magnetic localised Mn ions. 

L.W. Wang and N.F. Hu, Electrochemistry and electrocatalysis with myoglobin in biomembrane-like DHP-PDDA polyelectrolyte-surfactant complex films. J. Colloid Interface Sci. 236,166-172 (2001). Z.H. Dai, X.X. Xu, and H.X. Ju, Direct electrochemistry and electrocatalysis of myoglobin immobilized on a hexagonal mesoporous silica matrix. Anal. Biochem. 332, 23-31 (2004). 

Nguyen, T.Q., J. Wu, S.H. Tolbert, and B.J. Schwartz. 2001. Control of energy transport in conjugated polymers using an ordered mesoporous silica matrix. Adv Mater 13 (8) 609—h. 

Ehseev, A.A., Napolskii, K.S., Lukashin, A.V., Tretyakov, Y.D. Ordered iron nanowires in the mesoporous silica matrix. J. Magn. Magn. Mater. 272-276, 1609-1611 (2004)... 

Atomically dispersed titanium in a mesoporous silica matrix have also been well documented as successful catalysts in alkene selective oxidation reactions using [116,123,124]. 

Fattakhova-Rohlfing, D. Rathousky, J. Rohlfing, Y. Bartels, O. Wark, M. 2005. Functionalized mesoporous silica films as a matrix for anchoring electrochemically active guests. Langmuir 21 11320-11329. 

We also include in this class of quasi-2D nanostructured materials Titania deposited inside ordered mesoporous silica (because an inner coating of mesoporous silica may be realized), or nano-dot type Titania particles well dispersed in the ordered porous matrix. We do not consider here solids which contain linear or zig-zag type TiOTiO-nanowires in a microcrystalline porous framework, such as ETS-4 and ETS-10, notwithstanding the interest of these materials also as photocatalysts,146-151 because these nanowires are located inside the host matrix, and not fully accessible from the gas reactants (the reactivity is essentially at pore mouth). 

Poly(propylene amine) dendrimers containing 4, 8, and 64 amidoferrocene peripheral units have also been incorporated in the highly ordered channels of mesoporous silica obtaining a novel type of redox-active materials. One significant feature of these new composite materials is that the ferrocene units of the guest dendrimers are easily accessible to electrochemical oxidation, as revealed by studies carried out in MeCN solutions by using Pt electrodes derivatized with films of such dendrimer-matrix complexes.33... 

Matrix surface modifiers and organically modified mesoporous silica. For instance, methyltrialkoxysilane CH3Si(OR)3 or phenyltrialkoxysilane (C6H5Si(OR)3) are combined with TMOS or TEOS in order to modify the polarity of the matrix s surface for the preparation of the nanocomposites mentioned above. 

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