放射孔二氧化硅及其核壳结构的制备与表征

Preparation and Characterization of Radially Porous Silica and the Core-shell Structure

室温下以十六烷基三甲基溴化铵(CTAB)为模板剂,正硅酸乙酯(TEOS)为硅源,氨水(质量分数25%)为催化剂,在水-乙醇-乙醚作共溶剂的体系中以氨基化的实心二氧化硅(NH2-sSiO2)为添加剂,制备了放射孔二氧化硅及其核壳结构(sSiO2@rSiO2).通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、小角X射线衍射(XRD)、氮气吸附-脱附实验和孔径分布测定对其进行了表征和分析.结果表明,合成的产物为0.4～1μm的球形粒子,球上存在多级放射状孔道结构,孔径从3 nm到几十纳米的多级孔径并存,样品的Brunauer-Emmett-Teller(BET)比表面积为996 m2/g.最后对放射孔二氧化硅的形成机理及核壳结构的影响因素进行了初步探讨.

At room temperature and in water-ethanol-ethyl ether solution with adding amino-modified solid silica,radially porous silica and the core-shell structure were synthesized using hexadecyltrimethylammonium bromide（CTAB） as template,tetraethylorthosilicate（TEOS） as silica source and ammonia solution as catalyst.Scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,small angle X-ray diffraction technique（XRD）,Nitrogen adsorption-desorption isotherms and the corresponding pore size distribution were used to characterize the samples.Results show that spheres with diameters of ca.0.4—1 μm are obtained,the hierarchical and radial pores with the size from 3 nm to tens of nanometres are on the sample surface,and the BET surface area of the sample is 996 m2/g.The mechanism of radially porous silica and influential factors of core-shell structure were also discussed.