| Summary: | 碩士 === 國立成功大學 === 化學系碩博士班 === 94 === Abstract
Recently, neutral surfactant-templated mesoporous silicas have attracted much attention because the neutral surfactants are biodegradable and natural friendly. In addition, the mesoporous silicas prepared with the neutral surfactant possess thicker wall thickness than that synthesized with cationic surfactant. In general, a highly acidic condition (pH< 2.0) was required to fabricate the neutral surfactant-templated silicas. It is well known that most of metal ions are well dissolved in highly acidic solution but fast condenses to metal oxides in neutral and alkaline aqueous solution.
Introducing metal oxides into the mesoporous silica is relatively difficult to be achieved in a highly acidic solution. In this study, we proposed a simple method by mixing a acidic water solution of silicate, metal alkoxides, P123 surfactant with a alkaline solution to effectively incorporate the heteroatom of Al, Ti, or Zr into triblock copolymer templated mesoporous silicas in a near neutral reaction media (pH ~5.0) at room temperature.
In addition to the synthesis of metal-oxide containing mesoporous silicas, we used the mesoporous carbons of high surface area, large pore volume, highly stable carbon framework and easy removal by calcination as solid template to prepare the porous metal oxides. By using a simple convenient impregnation method, mixing the mesoporous carbons with metal ions or metal alkoxides in an acidic ethanol solution, drying at 60 oC gave the metal ions-containing mesoporous carbons. After annealing at 200–400 oC, and calcination at 600–700 oC the mesoporous metal oxides was prepared. This mesoporous carbon-templating technique can be applied to various metal oxides, such as MgO、α-Fe2O3、Al2O3、TiO2、ZrO2. Therefore, the porous metal oxides with high surface area, large pore volume and high crystalline have been efficiently prepared for the potential applications in catalysts and fuel cells.
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