Uniform nanoparticles of rutile and anatase were prepared, respectively, by a new approach, a microemulsion-mediated method, in which the microemulsion medium was further treated by hydrothermal reaction. Herein, the combined procedure of microemulsion and hydrothermal synthesis to prepare nanoparticles is referred to as a microemulsion-mediated hydrothermal (MMH) method. This MMH method could lead to the formation of crystalline titania powders under much milder reaction conditions than the normally reported microemulsion-mediated methods, in which posttreatment of calcination was necessary. In this work, a kind of solution was formed by dissolving tetrabutyl titanate into hydrochloric acid or nitric acid, and the solution was dispersed in an organic phase for the preparation of the microemulsion medium. The aqueous cores of water/Triton X-100/hexanol/cyclohexane microemulsions were used as constrained microreactors for a controlled growth of titania particles under hydrothermal conditions. The product of hydrothermal synthesis was separated and dried for characterization. The phase components and the morphologies and grain sizes of products were determined by X-ray diffraction (XRD) and by transmission electron microscopy (TEM). The effects of changing the variables of the reaction conditions, such as the use of acid, the concentrations of acid, the reaction temperatures, and/or the reaction times on the phases and morphologies of the titania product are described.

Hollow spheres of mesostructured lead titanate, denoted as PTM-1, have been prepared via a combined oil-in-water emulsion mediated and neutral amine supermolecular templated route. The variety of reaction temperatures and KOH concentrations indicates hollow spheres can be formed under a very critical condition. The structure and composition of the as-synthesized PTM-1 have been determined by powder X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), CHN (carbon-hydrogen-nitrogen) elemental analysis, and thermal analysis. Chemical extraction of organic templates by a cosolvent of weak acid and alcohol has resulted in the formation of a new mesoporous material of non-silica oxide with high porosity.

Tetragonal BaTiO3 powders were prepared hydrothermally, using Ba(OH)2·8H2O and TiO2 (anatase), in the absence of anions such as chloride ions, at a temperature of 220°C for several days. Characterization via X‐ray diffractometry, scanning electron microscopy, and differential scanning calorimetry confirmed that increasing the Ba:Ti molar ratios (from 1:1 to 4:1) and alkaline concentrations (from 1.0M to 3.0M) promotes the formation of tetragonal BaTiO3.