Hydrothermal Preparation Of TiO₂ Fibers And Complex Fluorides

Titanium oxide is an effective photocatalysis in the treatment of pollutants in wastewater and air. Power titanium oxide, the size of particles in the range of 5⁵0nm has better photocatalytic activity. The bleeding of the photocatalyst can be overcome by fixation but that results in decrease of its surface area and photoactivity. Titanium oxide fibers can overcome all those disadvantages. At present titanium oxide fibers are synthesized by sintering at high temperature. We attempted to synthesize these fibers by hydrothermal reactions. The influences of different mineralizer, hydrothermal processing temperature and mineralizer consistence on the morphology of the synthesized fibers were investigated in this dissertation. Titanium oxide fibers of high aspect ratio synthesized by hydrothermal synthesis have potential applications in photocatalysis and catalyst support. The morphology of the synthesized fibers was little different when potassium hydroxide and sodium hydroxide were used as mineralizer. The influences of V on the crystalline type were also investigated. The microstructures of titanium oxide fibers were characterized by SEM, TEM, XRD, FT-IR, TG-DSC methods.Four complex fluorides LiBaF₃, KMgF₃, KNiF₃, KZnF₃ were also synthesized by hydrothermal synthesis and were characterized by SEM, XRD methods. KZnF₃ had purity phase, even size and good morphology. It can be applied in many such as electricity, magnetism and photo. Compared with high-temperature solid-phase reaction hydrothermal reaction is characterized in no inert gases atmosphere, less contaminaint and mild reactive conditions.