1996 年 104 巻 1212 号 p. 715-718
A peroxo titanic acid (PTA) solution has been prepared by mixing titanic acid wet gel and hydrogen peroxide solution. The PTA solution was a neutral, transparent, stable liquid. The PTA crystallized to form an anatase phase after calcination at a temperature above 250°C. When the PTA solution was autoclaved at a temperature above 100°C for 6h, it changed to a sol containing anatase crystals less than 20nm in diameter. Aggregation occurred after autoclaving at a temperature above 120°C. When the PTA solution was heated to 100°C, it was translucent and stable in spite of containing ultrafine anatase crystals (9nm in diameter). It was deduced that the surfaces of anatase crystals are modified by the peroxo groups.