Crystalline mesoporous molecular sieves have long been sought as solid acid catalysts for organic reactions involving large molecules. We synthesized a series of mesoporous molecular sieves that possess crystalline microporous walls with zeolitelike frameworks, extending the application of zeolites to the mesoporous range of 2 to 50 nanometers. Hexagonally ordered or disordered mesopores are generated by surfactant aggregates, whereas multiple cationic moieties in the surfactant head groups direct the crystallization of microporous aluminosilicate frameworks. The wall thicknesses, framework topologies, and mesopore sizes can be controlled with different surfactants. The molecular sieves are highly active as catalysts for various acid-catalyzed reactions of bulky molecular substrates, compared with conventional zeolites and ordered mesoporous amorphous materials.

Zeolite MFI nanosheets have been hydrothermally synthesized using a surfactant with the formula [C 18 H 37 -N + (CH 3 ) 2 -C 6 H 12 -N + (CH 3 ) 2 -C 6 H 12 -N + (CH 3 ) 2 -C 18 H 37 ][Br À ] 3 as the zeolite structure-directing agent. These nanosheets correspond to a slice of MFI zeolite crystal of 1.5 nm thickness in the b-direction. Each nanosheet is composed of a monolayer of micropores, which is thinner than a single crystal unit-cell dimension (2.0 nm). Such a single-pore zeolite nanosheet still exhibits high thermal stability, steam stability, acid strength and shape-selective catalytic activity, comparable to the bulk crystal.

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Multiammonium surfactants exhibited a remarkable capping effect for zeolite synthesis in the forms of nanoparticles, nanorods, and nanosponges in cases where common monovalent surfactants failed. A nanorod-shaped mordenite zeolite synthesized in this manner showed significantly enhanced catalytic lifetimes in acid-catalyzed cumene synthesis reactions.