低表面活性剂浓度下有序介孔SiO_2的制备及性能

Synthesis and Properties of Ordered Mesoporous Silica in a Low Surfactant Condition

在碱性条件下 ,采用低浓度阳离子表面活性剂 ,利用表面活性剂与硅源水解后形成的聚集体相互作用 ,在溶液中形成分子自组装体 ,从而形成有序排列的介孔SiO2 材料·水热和室温碱性条件下 ,表面活性剂与硅源的粒子数比为 0 0 6∶1 ·由HRTEM分析 ,小角度XRD分析 ,TG DTA分析及FT IR分析等研究表明 :在较低的表面活性剂浓度下 ,通过分子自组装体做模板剂 ,最终反应物经一定工艺处理 ,可形成六方结构介孔SiO2 ·水热条件下使分子的作用增强 ,提高介孔骨架中硅原子的聚集度 ,由于铝原子的引入取代部分硅原子导致晶格增大 ,并使有序介孔结构保持完好·介孔SiO2 孔道大小 3～ 4nm ,六方结构排列·介孔结构保持完整的最佳煅烧温度为 5 0 0℃·

Ordered mesoporous silica was synthesized successfully in low surfactant condition. In an alkaline solution, cationic surfactant interacted with coaggregation of orthosilicate easter. The mole ration of surfactant to silica source is only 0 06∶1.The resulting materials were characterized by HRTEM, low angle XRD,TG DTA and FT IR. Much low surfactant can be used to synthesize mesoporous silica through molecular self assembly. By a special processing, ordered mesoporous silica was formed. In an hydro thermo condition, molecular interaction was increased, and coaggregation of silica in mesoporous structure was also enhanced. Lattice constants of mesoporous structure was increased when aluminum atom replaced silicic atom. It makes surfactant templating agent to be eliminated easily and mesoporous structure keep in good shape. The pore diameter of mesoporous silica was in 3?nm～4?nm and mesoporous structure was in a hexagonal packed state. The optimum calcined temperature, which keeps mesoporous structure in good shape, is 500?℃.