Direct synthesis of an anatase‐TiO 2 nanofiber/nanoparticle composite powder from natural rutile

A new, environmentally friendly route to obtain an anatase TiO 2 nanopowder from natural rutile sand is reported. The powder has been prepared via the direct hydrothermal process from natural rutile, followed by an ion‐exchanging with HCl (aq). The new TiO 2 powder possessed unique morphology, i.e., it was composed of anatase nanofibers (one to several tens μm in length and 10–50 nm in diameter) and anatase nanoparticles (about 10 nm in diameter). The direct hydrothermal process acted not only as a reaction step but also as a semi‐purification step (from 96%‐TiO 2 in natural source to 99%‐TiO 2 in final product). This new direct hydrothermal process can be an industrial process to prepare low‐cost TiO 2 chemicals from natural source. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)