Preparation, characterization and growth mechanism of ZrO2 nanosheets

High quality single-crystal zirconia nanosheets were successfully prepared via molten salt method, using solvothermally synthesized product as precursor. The effects of heat treatment temperature and soaking time on the phase composition and morphology of samples were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, Thermal analyzer, Raman spectrometer, Field-emission scanning electron microscope and Transmission electron microscope. The results show that zirconia nanosheets with a thickness of 60-80 nm and a width-thickness ratio up to 13 could be obtained by using NaCl and Na3PO4 as composite salts at 900 degrees C for 5 h. The precursors containing Zr-OH and Zr-O bonds have relatively high activity, which is beneficial to crystal growth. In addition, the as-prepared nanosheets with exposed (001) plane are monoclinic-structured and show no distinct defect. The growth behavior of particles during dissolution-recrystallization process is analogous to self-focusing mechanism. The preparation method can be extended to wet-chemical synthesis of other nanomaterials.