原位法制备介孔SiO_(2)@TiO_(2)粉体及其性能研究

In-situ Preparation and Properties of Mesoporous SiO_(2)@TiO_(2) Powder

介孔SiO_(2)@TiO_(2)粉体具有较大比表面积及有序的孔径分布,在吸附、药物控释以及催化剂载体等领域应用前景广阔。以正硅酸乙酯为硅源、钛酸正丁酯为钛源、十六烷基三甲基溴化铵为模板剂,结合并改进溶胶凝胶法和水解沉淀法,设计了一种原位制备介孔SiO_(2)@TiO_(2)粉体的方法。通过对不同酸碱条件下所得样品进行结构与性能分析表明,碱性条件有利于介孔SiO_(2)@TiO_(2)粉体的制备,在pH值为3和5时,其孔径分布不集中,比表面积在100 m^(2)/g以下,当pH值为7~11时,其比表面积为150~200 m^(2)/g,孔体积为0.213~0.399 mL/g,孔径集中分布在5 nm左右。相较于传统的溶胶凝胶法,原位法制备的介孔SiO_(2)@TiO_(2)粉体比表面积和孔体积均有增大,孔径减小但分布集中,使其更适合作为催化剂载体。

Mesoporous SiO_(2)@TiO_(2)powder has a large specific surface area and ordered pore size distribution,which brings a wide application prospect in the fields of adsorption,controlled release of drugs and catalyst support.In this study,with ethyl orthosilicate as silicon source,n-butyl titanate as titanium source and cetyl trimethyl ammonium bromide as template agent,a method for in-situ preparation of mesoporous SiO_(2)@TiO_(2)powder was invented by combining and improving sol-gel method and hydrolytic precipitation method.The analysis of the structure and properties of the samples obtained under the conditions of different pH shows that the alkaline condition is beneficial to the preparation of mesoporous SiO_(2)@TiO_(2)powder.When the pH value is 3,5,the pore size distribution is not concentrated,and the specific surface area is less than 100 m^(2)/g.When the pH value is 7~11,the specific surface area is 150~200 m^(2)/g,the pore volume is 0.213~0.399 mL/g,and the pore size distribution is concentrated about 5 nm.Compared with the traditional sol-gel method,the specific surface area and pore volume of mesoporous SiO_(2)@TiO_(2)powders prepared by the in-situ method increase,the pore size decreases but the distribution is concentrated,making it more suitable for the field of catalyst support.