Synthesis And Characterization Of Perovskite And Perovskite-type Composite Materials

The perovskite-type composite oxides are a series of important functional materials. They have significant promise in the fields of electrics, magnetics, luminescence and catalysis.In this paper, the glycine-nitrate combustion synthetic method was used to prepare La_0.3Ca_0.7Ni_0.7Co_0.3O₃ under different temperatures. It was found that La_0.3Ca_0.7Ni_0.7Co_0.3O₃ at 400℃possessed maximum catholic peak potential and minimum anodic peak potential. Perovskite complex oxides La_0.3Ca_0.7Ni_xCo_1-xO₃(x=0,0.25,0.7) and their polypyrrole composites PPY/La_0.3Ca_0.7Ni_xCo_1-xO₃(x=0,0.25,0.7) with 60% and 80% pyrrole were prepared by a glycine-nitrate combustion synthetic method and an in situ polymerization method, respectively. The structure,morphologies properties of the samples were characterized by means of powder X-ray diffractometer(XRD),Fourier transform infrared (FTIR) spectrometer,scanning electron microtscope(SEM).Cyclic voltammetry of PPY/ La_0.3Ca_0.7Ni_xCo_1-xO₃(x=0,0.25,0.7) was conducted in 1 mol·L-1 KOH solutions.It was found that PPY/La_0.3Ca_0.7Ni_xCo_1-xO₃ with 80% pyrrole possessed maximum cathodic peak potencial and minimum anodic peak potential.The ceramic powders of complex oxides La_0.6Sr_0.4Fe_0.2Co_0.8O₃ were prepared by the citric acid-nitrate combustion synthesis. The perovskite oxides were characterized by XRD, SEM and IR. The aniline/bovine hemoglobin (bovine serum albumin)/La_0.6Sr_0.4Fe_0.2Co_0.8O₃ complex is prepared in water. It is composed by aniline/ bovine hemoglobin (bovine serum albumin) and La_0.6Sr_0.4Fe_0.2Co_0.8O₃ nanocrystalline composite oxide. bovine hemoglobin (bovine serum albumin) and aniline monomer are assembled to La_0.6Sr_0.4Fe_0.2Co_0.8O₃ nanocrystal surface, then La_0.6Sr_0.4Fe_0.2Co_0.8O₃ nanocrystalline on which bovine hemoglobin (bovine serum albumin) is adsorbed is covered by aniline. Finally, polyaniline/ bovine hemoglobin (bovine serum albumin)/La_0.6Sr_0.4Fe_0.2Co_0.8O₃ composite materials is prepared by the chemical oxidation of the aniline/ bovine hemoglobin (bovine serum albumin)/ La_0.6Sr_0.4Fe_0.2Co_0.8O₃ as the precursor. The degradation experiment was performed by photo catalytic methods. A fluorescent Hg lamp was used as irradiation source. The catalytic activity of composite materials was studied with UV-Vis.Perovskite complex oxides La_0.3Ca_0.7Ni_0.25Co_0.75O₃ were prepared by a glycine-nitrate combustion synthetic method. A set of silver-modified Ag/La_0.3Ca_0.7Ni_0.25Co_0.75O₃ prepared under different light-sources are used to degrade acid red B.The structure,morphologies properties of the samples were characterized by means of powder X-ray diffractometer(XRD),scanning electron microtscope(SEM). It was found that Ag/ La_0.3Ca_0.7Ni_0.25Co_0.75O₃ with 2% Ag under UV irradiation was shown high catalytic activity for the degradation of acid red B.