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.

This review covers the sustainable development of advanced improvements in CO2 capture and utilization.

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Titanosilicate MFI (a three-letter structural code among ∼200 zeolite framework codes) nanosheets of single-unit-cell thickness were synthesized with a diquaternary ammonium surfactant as the zeolite structure-directing agent, that is, C16H33–N+(CH3)2–C6H12–N+(CH3)2–C6H13. The resultant titanosilicate nanosheet possessed a large intersheet mesopore volume with high surface area due to the nanomorphic crystalline architecture as well as the isomorphically incorporated titanium species. Thus, it exhibited notable catalytic activities with high epoxide selectivity for bulky molecular epoxidation reactions using H2O2 or t-butyl hydroperoxide as an oxidant. In addition, the catalytic performance could be enhanced via postsynthetic fluoride treatment with NH4F that can reduce the surface silanol groups and, hence, increase the surface hydrophobicity.