| In this dissertation, rare-earth oxide nanoharness and titanium dioxide nanoshuttles have been successfully synthesized through choosing appropriate reactant and surfactant in1-octadecene and ethanol system. With the titanium dioxide nanoshuttles as carrier and ethanol as reductant,we got the composite of Ag/TiO2.The samples we prepared are analyzed and characterized by transmission electron microscope, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy analysis, Uv-vis spectrometer, Fourier transform infrared spectrometer, fluorescence spectrometer and Gas Chromatography-mass Specrometer. The major conclusions are as follows:1. In the system of1-octadecene, oleic acid roles as surfactant, yttrium nitrate and urea roles as precursors, yttrium oxide nanoharness with uniform morphology and size are prepared under certain conditions. After a series of control experiments, we found these nanoharness are dynamic stable, the morphology keeps constant in a long time. Reserch results demonstrate that the components of precursors and reaction temperature all both play a part in the formation of product, the morphology chang with the both factors. Besides, the polarity of the solvent also has an effect on it, keep other conditions unchange, add a small amount of water to this system, the morphology of nanoharness keeps good whereas the crystal phase changes. Furthermore, the product is sensitive to the kind of surfactant, adding different amounts of dedodecylamine can get different nanostructures, such as yttrium oxide nanobelts and nanospheres. Combined with the FT-IR and TG-DTA analysis, a possible mechanism is proposed to explain the formation of nanoharness. This method is a general and suitable way, which can be used for the synthesis of holmium oxide, ytterbia oxide and erbium oxide nanoharness.2. Choosing the ethanol as solvent, tetrabutyl titanium as the original resource, oleic acid and dedodecylamine as the surfactants, titanium dioxide nanoshuttles are successfully gained via the solvothermal method. TEM and SEM analysis suggest that the product is unifom in size and morphology, HRTEM analysis suggests that the crystal grows along the (001) and (101) crystal facets. XRD analysis indicates the sample is pure anatase phase with good crystallinity. EDS analysis shows that the product is very clean, easy to use in practice. Heated TiO2nanoshuttles at different temperature to learn the relationship between morphology, phase and temperature, we found nanoshuttles split more and more severely with the rise of temperature, the anatase phase began to transform to rutile phase at550degree centigrade. Through TG-DTA and FT-IR analysis, we learnt that TiO2surface is mainly covered by oleic acid and dedodecylamine, in the formation process of TiO2, oleic acid roles as complexing agent and initiating agent, dedodecylamine roles as nucleophiles, complexing agent and guiding agent. This paper discussed the influence of reaction time, molar ratio of oleic acid and amine, solvent composition and reaction temperature on product and finally put forward the formation mechanism of nanoshuttles.3. In the system of ethanol, ethanol plays a part of solvent and reductant, when heated to some temperature, it can reduce silver nitrate to silver elementary substance and form the composite of Ag/TiO2. A mechanism is put forword to explain the reductibility of ethanol. This preparation method is simple and suitble for preparing other inert metals-loaded titanium dioxide nanostructures. Choose this composite as the catalyst of aromatic nitro hydrogenation broaden its applied range. Experiment results suggest that this catalyst is high efficient and has a broad potential application prospects in industrial production. In this paper, we described the transformation mechanism of aromatic nitro to arylamine, which deepened our understanding about the catalytic hydrogenation of aromatic nitro compounds. |
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