The growing significance of nanocrystalline inorganic functional materials in the fields of catalysis, electronics, and energy conversion together with the increasing demand of the society for safer, softer, and “greener” technologies has drawn considerable attention of the researchers toward water-based solution processes for synthesis of such materials. In this respect complex oxides, containing d0-transition metals, such as Ti, Nb, Ta, or Si represent an outstanding challenge for materials chemists due to the extremely narrow range or almost complete absence of suitable precursor compounds compatible with aqueous systems. In the recent 10 years, a remarkable progress has been achieved in the development of new water-soluble complexes of titanium and considerable experience was accumulated in the application of these compounds for synthesis of nanocrystalline titanium-containing materials. The essential knowledge of coordination chemistry of such water-soluble titanium complexes is reviewed in this work, which succeeded to identify the key structural features responsible for stability of the compounds against hydrolysis and to provide guidelines for synthesis of these complexes. Finally, an extensive overview of highly selective aqueous solution based synthesis of TiO2 polymorphs as well as complex oxide materials with the help of the novel water-soluble titanium complexes is provided.

Flux treatment using various molten salts was performed for SrTiO₃ powders. Morphology of SrTiO₃ crystals obtained by the flux treatment strongly depended on the kinds of molten salts used. Large cubic crystals exposing {100} facets with a size of 5–6 μm were obtained by the flux treatment with LiCl whereas truncated cubes exposing {100} and {110} facets with a size of 200–400 nm were obtained when NaCl or SrCl₂ was used as a flux reagent. In contrast, the flux treatment with KCl gave characteristic shaped crystals with a size of 300 nm. Electron microscope observation and electron diffraction analysis revealed that the crystals treated with the KCl flux expose {100}, {120}, and {121} facets. SrTiO₃ treated with the KCl flux exhibited higher activity by 20 times than the non-flux-treated sample. Thus, a remarkable improvement of activity has been achieved by the fabrication of SrTiO₃ crystals exposing high-index facets, {120} and {121}, using the KCl flux.