Synthesis of Barium Titanate Nanoparticles from Decomposition of Barium Titanyl Oxalate Tetrahydrate with Aid of Supercritical Water

摘要

A novel process of BaTiO_3 manufacture was conducted by using supercritical water. Preparation of BaTiO_3 nanoparticles was investigated from decomposition of BaTiO(C_2O_4)_2·4H_2O (BTOT) with aid of supercritical water for the first time. When BTOT was exposed to supercritical water around 673 K and 30 MPa, it decomposed quickly in 5-22 seconds. The products formed strongly reply on environmental conditions. BaCO_3 and TiO_2 were always observed as the products in the absence of alkaline additives. BaTiO_3 nanoparticles with specific surface area as high as 12～14 m~2/g were able to be obtained under strong alkaline conditions, such as NaOH/CO_2=2/1. It was found that environment of supercritical water was better than sub-critical conditions to obtain high quality BaTiO_3 particles with fewer defects. Employment of supercritical water significantly reduced the reaction time and temperature compared to other BaTiO_3 manufacture processes utilizing BTOT as precursor.