Photocatalytic properties of rutile nanoparticles obtained via low temperature route from titanate nanotubes

Acid treatment of titanate nanotubes with 0.1 mol dm−3 H2SO4 results in their transformation into various forms of nanostructured TiO2, the shape and crystal structure of which depend on the temperature and time of treatment. Such a transformation at 25 °C results in the formation of rutile spheroidal nanoparticles, which are characterized by good crystallinity, high specific surface area (ca 250 m2 g−1 BET) and small average diameter of particles (ca. 3 nm). These particles are also characterized by increased activity in reactions of both photocatalytic generation of hydrogen from alcohol and advanced oxidation of organic species (ethanol). Acid assisted transformation of nanotubes at higher temperatures results in formation of nanostructured anatase/titanate composites with lower photocatalytic activity. The mechanism of transformation and the reasons for increased activity of rutile nanoparticles are discussed.