Hierarchical macroporous microporous silicas

Figure 10.3 Exo-templating the method of Stein can be used to create hierarchical macroporous/microporous (or macroporous/mesoporous) silicas.

The synthesis of a hierarchical pore structure, combining the macroporous diatomaceous earth with microporous zeolites, is reported. Diatomaceous earth is an abundant and varied source of macroporous silica which has been zeolitisatised to produce a bifunctional, hierarchical composite. A range of different zeolites have been synthesised to generate different pore architectures, hydrophobic/hydrophilic materials and ion-exchange/catalytic properties. 

Fujita S, Nakano H, Ishii M, Nakamura H, Inagaki S (2006) Preparation of hierarchical porous silica and its optical property. Microporous Mesoporous Mater 96 205 Holland BT, Abrams L, Stein A (1999) Dual templating of macroporous silicates with zeolitic microporous frameworks. J Am Chem Soc 121 4308 Yamauchi Y, Kuroda K (2006) Fabrication of a Pt film with a well-defined hierarchical pore system via solvent-evaporation-mediated direct physical casting. Elec-trochem Commun 8 1677... 

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