Study And Application Of Composite Materials Based On Perovskite Nanoparticles

In recent years, organic polymer-inorganic nanocomposites research has become very attractive. This material will have hope be used in optics, electromagnetism, mechanics, biology and other fields.In this dissertation, the composite oxide of La_0.7Ca_0.3Fe_0.25Co_0.75O₃ nanocrystalline has been synthesized by glycine-nitrate combustion method. The La_0.7Ca_0.3Fe_0.25Co_0.75O₃ crystal species and grains are characterized by XRD, SEM, EDS and IR measurements. The results show that La_0.7Ca_0.3Fe_0.25Co_0.75O₃ grains are spherical, diameter is 19.1mm, under the situation of reunion. At the same time, Chitosan/La_0.7Ca_0.3Fe_0.25Co_0.75O₃ Nanocomposite Films has been synthesized by sol-gel method in the solution of chitosan, and its surface, composition changes as well as the particle sizes were analysed by the above analytical method. The result show that there is a strong hydrogen bond between the interaction of chitosan and La_0.7Ca_0.3Fe_0.25Co_0.75O₃ , the molecular interaction disrupt the original crystal structure of the chitosan. The new molecular array was generated in the complex process between chitosan and La_0.7Ca_0.3Fe_0.25Co_0.75O₃ . So that good dispersion and compatibility can be formed between the two groups.A novel nanocomposite photocatalyst PMo₁₂/PPy/La_0.7Ca_0.3Fe_0.25Co_0.75O₃ has successfully been prepared first by using a chemical oxidation method with (NH4)2S208 as an oxidant to form PPY/La_0.7Ca_0.3Fe_0.25Co_0.75O₃ nanoparticles and then by an electrostatic assembly of PMo₁₂3- anions. The resulting materials are characterized by XRD, SEM, FT-IR techniques. Photocatalytic performance test is taking low concentration of methylene blue dye solution as the degradation of target. The results show that the load modification of PMo₁₂ improved the photocatalytic activity of La_0.7Ca_0.3Fe_0.25Co_0.75O₃ /PPy.La_0.7Ca_0.3Fe_0.25Co_0.75O₃ nanoparticles were immobilized on CS(chitosan) using cross-linking processing. The resulting materials were characterized by XRD, SEM, FT-IR techniques respectively. The effects of some factors were studied by the degradation of acid orange dye under mercury lamp irradiation. The results showed that the catalyst could degrade acid orange dye effectively, and the decolorization rate can reach 99%.A uniform film of polypyrrole was electrochemically polymerized and immobilized on the surface of glassy carbon electrode(GCE), and a layer of La0.7Sr0.3NiO3 and chitosan(CS) composite film was absorbed on the surface of PPY film. Preparation of the enzyme modified electrode ,used as biosensor for determination of H₂O₂ , was finally completed by immobilization of the bovine hemoglobin(Hb) on to the surface of La0.7Sr0.3NiO₃ /CS/GCE. The modified electrode was characterized with cyclic voltammetry (CV) and scanning electron microscope (SEM). The biosensor displays excellent catalytic activity and rapid response for H₂O₂ . The linear range for the determination of H₂O₂ is from 7.0×10^-6 to 1.5×10^-3 mol/L with a detection limit of 9.0×10^-8 mol/L.