| Perovskite oxides(ABO3) is one of the main branch of rare-earth nano-materials. As a new treasure trove of the rare-earth materials, it had excellent performance in optical, magnetic, and electric. At the same time, these substance are also caused by both nano-scale special effects, it would become the new material of 21st century. It has widely used as solid electrolytes, sensors, high temperature heating materials, solid resistors, solid fuel cell and catalyst. Because the perovskite can replace the precious metal as the efficient catalysts, it caused widespread concern in academia and research boom. This paper focuses on the perovskite oxide preparation and use of nanotechnology to improve the catalytic activity of materials. Topicals include:(1) Preparation and Photocatalytic Properties of Rattle Structure of Ag@ LaCoO3.Using hydrothermal method to synthesize the best shape of Ag@C nanoparticles as the template, by ultrasonic dispersion coating La3+, Co+.After 500℃calcined, we got the black powders.Through XRD, SEM, UV-vis, IR and other tests means for analysising, the main component of the powders was Ag@LaCoO3. It had the rattle structure which had a core in the center of the hollow sphere.This structure both had the properties of the core and shell. We did the photocatalytic degradation on Methylene Blue(MB) solution by using this Ag@LaCoO3 as the catalyst. As a result, the sample did a good efficacy on the MB dye. Meanwhile, we also discussed and research on the formation condition for the Ag@C nanoparticals. Improve the concentration of Ag+,added surface active agent and annealing under hydrogen protection, using SEM, IR to characterize the samples, we found that the best condition to get the Ag@C nanoparticals was at the 180℃for hydrothermal reaction 8 hours. It was the single dispersed nanoparticals with the Ag as the core and carbon as shell coated the Ag core. But after improving the concentration of Ag+,there were some rod with multi-core.Added surface active agent made the products'shell more thick and some tube appeared, through the annealing, there were only some weaken of -OH group and enhance of-CH3 group.(2) Preparation and Characterization for La0.6Sr0.4CoO3Using the hydrothermal carbonization of glucose to adsorb ions in one-pot synthesis method for getting La0.6Sr0.4CoO3, explore the effect of different calcination temperature on the product's crystal structure. It was found that the glucose formed the carbon templates during the hydrothermal reaction, the surface of the carbon had many hydroxyl and carbonyl groups.They can effectively adsorbed the La. Co,Sr and other ions, after a certain temperature calcine, removed the carbon fractions and left the metal composite oxides La0.6Sr0.4CoO3. Because the traditonal methods for synthesising perovskite oxides were combustion or sol-gel, our experiment was very simple and green than the traditional methods.(3) Synthesis and Characterization forLaCo03 based on the EG templete.Using expanded graphite(EG) as template to adsorb La,Co ions, made the precursor calcined at a high temperature, observed by SEM, different from the carbon spheres template, EG wouldn't be remove under 800℃, Because of the 700-800 high degree temperature calcination,the final product's peaks in the XRD patten showed very sharp, it means that the product had a good crystallinity. But the carbon spheres template would be removed at 500℃, if the temperature went up, the sphere structure of the oxides would collapse. The formation of perovskite oxides had a framework like the EG, it provide a good degradability and it has a good prospect. |
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