Synthesis and characterization of carbon sphere-silica core–shell structure and hollow silica spheres

Carbon sphere-silica core–shell structured material was prepared in the presence of cetyltrimethylammonium bromide using tetraethyl orthosilicate as precursor of silica by a sol–gel method combined with Stöber method. Carbon sphere cores with an average diameter of 300 nm were prepared by the pyrolysis of acetylene. After carbon sphere cores were removed by calcinations, hollow silica spheres with smooth surface and uniform shell thickness around 110 nm were obtained. The core–shell structure of carbon sphere-silica composites and the hollow structure of silica spheres were characterized by FESEM, HRTEM, XRD, XPS and FTIR. The results indicate that the silica was coated on the surface of carbon spheres. The inner diameter of the hollow silica spheres with amorphous shell was about 290 nm. A possible formation mechanism of the core–shell structure of carbon sphere-silica and hollow silica spheres was proposed.