SYNTHESIS OF PEROXO-MODIFIED ANATASE SOL FROM PEROXO TITANIC ACID-SOLUTION

A peroxo titanic acid (PTA) solution has been prepared by mixing titan ic 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 degrees C. When the PTA solution was autoclaved at a temperature above 100 degree s C for 6h, it changed to a sol containing anatase crystals less than 20 nm in diameter. Aggregation occurred after autoclaving at a tempera ture above 120 degrees C. When the PTA solution was heated to 100 degr ees C, it was translucent and stable in spite of containing ultrafine anatase crystals (9 nn in diameter). It was deduced that the surfaces of anatase crystals are modified by the peroxo groups.