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摘要
Mesoporous aluminas (MAs) with tunable structural properties, including BET surface area, pore volume and pore size, were successfully synthesized based on a sol-gel process via hydrolysis of aluminium isopropoxide associated with a structure-directing agent (SDA) as template in an acidic aqueous system. The effect of template type, template addition amount and inorganic aluminium precursor doping on the structural properties of the resulting MAs were systematically investigated. Four templates, including two non-ionic triblock copolymers P123 and F127, an amine based cationic quaternary surfactant cetyltrimethylammonium bromide (CTAB) and an anionic surfactant sodium dodecyl sulfate (SDS) were examined at varying amount. Three inorganic aluminium precursors, viz aluminium sulfate, aluminium nitrate and aluminium chloride, were used as the substitution aluminium sources to aluminium isopropoxide. The MAs synthesized were characterized using thermogravimetry - differential thermal analysis (TG-DTA) for decomposition and mass loss characteristics upon calcination, X-ray diffraction (XRD) for bulk crystallinity, transmission electron microscopy (TEM) for nano-scale morphology and N-2 physisorption techniques for porous structural properties. For a given SDA, increasing the amount of surfactant addition markedly improved the porosity of the MA synthesized. In terms of the ability to influence the structural properties of the resulting MAs such as BET surface area, pore volume and pore size, the SDAs tested followed a descending order of F127 > P123 > CTAB > SDS. MAs with the greatest pore volumes and pore sizes with narrow PSDs were obtained when the doping ratios of Al(NO3)(3), AlCl3 and Al-2(SO4)(3) were 15%, 30% and 2%, respectively. Depending on the type and addition amount of SDA and the aluminium precursor composition, the BET surface area, pore volume and pore size of MAs could be adjusted in the ranges of 178 m(2) g(-1) similar to 358 m(2) g(-1), 0.4 cm(3) g(-1) similar to 1.9 cm(3) g(-1) and 5.5 nm-30.1 nm, respectively.
- 出版日期2016-3-15
