Role of Ti-O bonds in phase transitions of TiO2.

A phase transition was achieved from TiO2 particles to titanate nanotubes by the breakage of Ti−O bonds without using expensive precursors, high temperatures, high chemical concentrations of alkaline solutions, and long synthesis times. The controlled preparation of one-dimensional nanostructures of titanates (H2Ti4O9·nH2O) has been conducted at a very low concentration of alkaline solution (1 M NaOH), and in a very short time (12 h) using TiO2 anatase and TiO2 P-25 (precursors) and a microwave enhanced soft chemical process. Temperature was used as a variable, and only low process temperatures (100−110 °C) were used. A combination of anatase nanoparticles/hydrogen tetratitanate nanotubes was synthesized using TiO2 (anatase) and a temperature of only 100 °C. When TiO2 (P-25) was used with the same concentration of alkaline solution (1 M NaOH), the same processing time of 12 h, and a higher temperature at 110 °C, only hydrogen tetratitanate nanotubes were observed. The linkages of “Ti−O” play a very import...