Synthesis and characterization of monoclinic TiO2 nanosheets

A novel two-step method for the synthesis of monoclinic titanium oxide (i.e. TiO2(B)) nanosheets is presented in this report. The method is featured by two steps: 1) synthesis of hydrogen titanate nanosheets, followed by 2) calcination of the titanate nanosheets at elevated temperatures. The hydrogen titanate nanosheets were prepared first by autoclaving anatase TiO2 powders, obtained by air calcining an ethanol-gel of Ti(OH)4 at 500 degrees C, in aqueous NaOH (10 mol/L) at 150-200 degrees C, and then by washing with hydrochloric acid under supersonic irradiation. While sizes of the nanosheets were found to increase with increasing the temperature of the hydrothermal treatment, the calcination at 400-500 degrees C of the hydrogen titanate nanosheets that were synthesized at higher autoclaving temperatures (180-200 degrees C) produced monoclinic TiO2 nanosheets with a uniform morphology. By contrast, the same calcination of the titanate nanosheets synthesized at the autoclaving temperature 180 degrees C led to anatase TiO2 nanoparticles.