Effect of solvents on morphology and structure of barium titanate synthesized by one-step hydrothermal method

Tetragonal barium titanate was synthesized from barium hydroxide octahydrate and titanium tetrachloride through a simple one-step hydrothermal method. The effect of different solvents on the crystal structure and morphology of barium titanate nanoparticles in the hydrothermal process was investigated. Except for ethylene glycol/water solvent, impurity-free barium titanate is synthesized in pure water, methanol/water, ethanol/water and isopropyl alcohol/water mixed solvents. Compared with other alcohols, ethanol is favorable to the formation of tetragonal structure. In addition, characterization studies confirm that particles synthesized in methanol/water, ethanol/water, isopropyl alcohol/water mixed solvents are smaller in size than those in pure water. In the case of alcohol-containing solvents, the particle size decreases in the order of isopropanol, ethanol and methanol. Among all the media employed, ethanol/water is the optimum reaction media for barium titanate in terms of high tetragonality (c/a=1.0088) and small average particle size (82 nm), which has great potential for practical application in multilayer ceramic capacitors.