Study On The Synthesis And Properties Of Atio₃ (a = Fe, Co, Ni) Nanocrystallines

Titania (TiO₂) and ATiO₃ (A = Fe, Co, Ni) nanocrystallines could be used to produced important semiconductors, which had many important applications in photocatalysis, electronics, and magnetics. The precipitation as precursor was synthesized via homogeneous precipitation method, and then it was calcined to form nanocrystallines. The properties of nanocrystallines were analyzed and discussed.It was easier to synthesize precursors possessing equably sizes by controlling the hydrolysis rate of urea in homogeneous precipitation method. It was found that the addition of H+ and some transition elements including Fe³⁺, Co²⁺, and Ni²⁺ enhanced the hydrolysis rate of urea and reduced the reaction time. The microstructures, characteristics, morphology and photocatalytic activity were studied by means of thermogravimetric and differential scanning calorimetric analyses (TG-DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), pore size analyzer, UV-Vis diffuse reflectance spectroscopy (UV-Vis), etc.The nanocrystallines of Fe2TiO5, CoTiO₃, or NiTiO₃ were synthesized when the precursors were calcined at 800℃for 6h. The nanocrystallines had fewer defects and granula size were smaller than 100nm. Compared with the as-prepared TiO₂ nanocrystallines, ATiO₃ nanocrystallines had less average surface areas.To investigate their photocatalytic activities, the as-prepared samples were applied in the decomposition of methylene blue solution under UV irradiation. Although the as-prepared ATiO₃ samples had lower catalytic activities, their UV-Vis spectra exhibited red shifts that suggested their light absorption scope extended to the visible light region and their gap band energies became narrow.