title: Ordered hexagonal mesoporous aluminosilicates with low Si/Al ratio: synthesis, characterization, and catalytic application.
abstract: Ordered hexagonal mesoporous aluminosilicates with lower Si/Al ratio below 5 have been successfully synthesized via the co-assembly of preformed aluminosilicate precursors with Gemini surfactant [C12H25N+(CH3)2(CH2)6N+(CH3)2C12H25] x 2Br(-) as the template. Powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N2 adsorption-desorption isotherm measurements, Fourier transform infrared spectroscopy, 27Al nuclear magnetic resonance, thermogravimetric analysis, and temperature-programmed desorption of cyclohexylamine are employed to characterize the resulting samples. The phenol alkylation reaction is carried out to evaluate their catalytic performances. These studies indicate that the sample with a low Si/Al ratio of 3 still retains a highly ordered hexagonal mesoporous structure. And it also possesses the highest acidity of 0.96 mmol among the samples with lower Si/Al ratios below 5 due to its higher specific surface area together with more content of tetrahedrally coordinated Al in the framework. The catalytic tests confirm that the acidity of the samples plays a key role in determining their catalytic performances.
authors.forename: Aifeng
authors.initials: A
authors.lastname: Liu
authors.forename: Hongwei
authors.initials: H
authors.lastname: Che
authors.forename: Chuanzhi
authors.initials: C
authors.lastname: Liu
authors.forename: Quanrong
authors.initials: Q
authors.lastname: Fu
authors.forename: Ruijiao
authors.initials: R
authors.lastname: Jiang
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry*; D002384:Catalysis; D003460:Crystallization / Q000379:methods; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D008968:Molecular Conformation; D010316:Particle Size; D016062:Porosity; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; D046911:Macromolecular Substances; C049037:aluminosilicate; D000535:Aluminum; D012825:Silicon