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

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.