Microemulsion-based synthesis of nanoscale TiO2 hollow spheres

Nanoscale TiO2 hollow spheres are prepared based on gelatine-filled reversed microemulsions. The resulting nanomaterial exhibits an outer diameter of 25–35 nm, a thickness of the sphere wall of 4–6 nm and an inner cavity of 15–20 nm in diameter. The as-prepared hollow spheres are characterized based on different electron microscopic techniques, infrared spectroscopy and optical spectroscopy. Thermogravimetry, X-ray powder diffraction and sorption measurements according to the Brunauer–Emmett–Teller analysis are used to elucidate the thermal properties as well as the specific surface of the hollow spheres. Finally, the photocatalytic properties of as-prepared TiO2 hollow spheres are studied.