Fabrication of TiO2 nanospheres by template replication in porous carbon networks

A silica-colloidal template approach was used to prepare monodisperse nanospheres of TiO2. Close-packed arrays of silica spheres were infiltrated with a sucrose precursor used as a source of carbon. The infiltrated sucrose was carbonized by calcination at 800 degreesC in flowing argon. After removal of the silica spheres by washing with HF, a porous carbon replica remained. The resulting pores in the replica were then filled with a chloroform solution of titanium alkoxide. Nanospheres of TiO2 approximately 200 nm in diameter were obtained after calcination of the organic component at 600 degreesC in an argon atmosphere and subsequent sintering in air at 700 degreesC.