Hydrothermal Synthesis Preparation, Characterization And Nonlinear Optical Properties Of Low-dimension TiO₂/Titanate Nanomaterials

Because of the specific electronic, optical, thermodynamic, and physical chemistry properties of titanate nanostructures, titanate nanomaterials have potential applications in the fields of catalysis, ion exchange, lithium batteries, and solar cells. In recent years, the preparation and research of nanostructures based on titanate has attracted considerable attention. Different nanostructured titanates were prepared by hydrothermal treatment of Ti powder or P25 at different concentration of NaCl or different temperatures under alkaline hydrothermal condition. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible absorbance, Fourier-transform infrared, and Raman spectroscopies. The influence of NaC1 concentration on structure, morphology, and composition of titanate nanostructures was investigated. Z-scan technology was used to investigate the nonlinear optical (NLO) properties of different morphologies of titanate products. Finally, this paper was offered as a preliminary probe into a study on the preparation of two-dimension layered titanate nanomaterials.Using Ti powder as raw material in the presence of NaCl, Ti powder treated with NaOH initially formed three-dimensional nanobelt microspheres. Nanobelt growth along [110] axis orientation was inhabited, and the nanobelts were transformed into wide nanoplates. At high concentrations of NaCl, nanosheets were exfoliated from the large particles through dissolution-recrystallization, and finally rolled into nanotubes. The protonic layered titanates were prepared through ion exchange of HC1 with calcined product which was followed by treating of Na2CO3 with TiO2(1:3 in molar ratio) at 800℃ for 20 h. Then the two-dimension layered titanates were prepared by stirring of protonic layered titanates with TBAOH solution. The NLO properties of titanate nanomaterial were influenced by its morphology at the same incident energy. The NLO properties of one-dimension titanate nanotubes were the most outstanding, follows were the zere-dimension nanoparticles, and the three-dimension nanoflowers.