Hydrothermal Synthesis Of PbTiO₃ And LiTiO₂ Nanostructures And Their Photoluminescence And Photocatalytic Properties

The ferroelectric oxides nanosheets and the semiconductor catalyst have increasingly shown a great potential application in the field of high-density nonvolatile memory and visible light photocatalytic, respectively. We here reviewed the research progress of TiO2 and Ti-based perovskite structure semiconductor photocatalytic and studied on the hydrothermal synthesis of PbTiO3 nanosheets, Li doping PbTiO3 nanoparticles and octahedral-shaped rock-salt LiTiO2 nanoparticles. Their photoluminescence and photocatalytic properties were also studied. The main results are summarized as following:(1) Single-crystalline tetragonal perovskite lead titanate (PbTiO3) nanosheets have been successfully hydrothermally synthesized by employing the as-prepared K2Ti6O13 nanofibers as titanium sources. And with the basis of a series of time-dependent experiments results, the layered K2Ti6O13 plays an important role in the preparation of PbTiO3 nanosheets. Furthermore, the indirect band gap PbTiO3 nanosheets exhibit strong PL emission, because of relative high density of surface state in the PbTiO3 nanosheets.(2) Li-doped PbTiO3 nanoparticles can be successfully synthesized by introducing LiNO3 in the hydrothermal system either with K2Ti6O13 nanofibers or tetrabutyl titanate as titanium sources. While, because of the reactivity of Ti hydroxyl oxide which formed by tetrabutyl titanate is higher than K2Ti6O13 nanofibers, the obtained Li-doped sample can get higher concentration of Li doping and smaller size of the nanoparticles. Moreover, a mass of Ti3+ and O2- vacany defects (due to the Li doping) have been introduced in the crystal lattice of PbTiO3, which makes the Li-doped PbTiO3 sample has good visible-light catalytic properties.(3) Rock salt LiTiO2 octahedral nanoparticles self-assembled by small grains have been first successfully synthesized via a facile hydrothermal method by introducing K2Ti6O13 nanofibers as titanium source, LiOH as lithium source, and KOH as mineralizer, respectively. And there are large numbers of Ti3+ and O2- vacany defects existed in LiTiO2 crystal lattice, which endows the octahedral-shaped LiTiO2 nanoparticlaes of real good visible-light photocatalytic activity. The photodegradation of MB aqueous using octahedral-shaped LiTiO2 nanoparticles as photocatalysts can be completed by nearly 100% after only 20min under visible light irradiation.