酸化チタンに於ける相転移の炭素被覆による抑制

Abstract

Phase transformation from anatase to rutile in titanium dioxide TiO_2 was found to be suppressed by carbon coating. The phase transformation in a commercially available anatase-type TiO_2 photocatalyst (ST-01) was suppressed from the heat treatment temperature of about 700℃ without carbon coating to that above 1100℃, and that in TiO_2 prepared from titanium alkoxide from 600℃ to 800℃. The suppression effect was the more pronounced by the more amount of carbon coated. This is caused by the disturbance of sintering and grain growth of TiO_2 particles by carbon coating. Due to this suppression, high crystallinity of anatase phase was possible to be realized without marked phase transformation to rutile, which was known to be preferable for photodecomposition of pollutants in water.