Direct synthesis of photocatalytically active rutile TiO₂ nanorods partly decorated with anatase nanoparticles

TiO₂ rutile nanorods either decorated with anatase nanoparticles or pure have been prepared via a facile single-step hydrothermal method using commercially available aqueous solutions of titanium bis(ammonium lactate) dihydroxide at natural pH (∼8.0) without any additives. The obtained powders have been characterized by X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, and nitrogen adsorption. The photocatalytic activities have been evaluated for the gas-phase decomposition of acetaldehyde under UV(A) illumination. The results revealed that TiO₂ rutile nanorods decorated with anatase nanoparticles exhibit a higher photocatalytic activity than those embedded in anatase nanoparticles or without any anatase contact. This behavior is explained by the better charge carrier separation in the case of anatase rutile mixtures.