| CuxO(x=1,2) micro-nano materials, as a kind of transition metal oxide semiconductor materials, because of its low price, easy preparation, as well as special photoelectric properties, magnetic and catalytic properties, are widely used in various gas sensors, biosensors, assisted photocatalytic degradation of organic pollutants, catalysis, harmful gas detection, supercapacitor, lithium ion battery, field emission electrode etc. Many methods have been used to prepare the materials, for example, gas phase reaction, liquid phase reaction, gas-liquid-solid reaction method. In this thesis, we select simple liquid phase method to control the growth of nano-or micro-CuxO materials with different morphologies and discuss the influence of morphology or dopping of CuxO on their photoelectric and storage performance. We expect to explore some good application prospect for CuxO nano and micro materials.1. The preparation of the Cu2O polyhedrons with different index surfaces and Cu2O opening hollow spheres, and the research of the relationship between the morphology of crystal and the catalytic effect of ammonium perchlorate (AP) thermal decomposition.Cuprous oxide (Cu2O) is a kind of P type or N type semiconductor material with a band gap of2.17eV. It has been reported that Cu2O with different mophologies exhibited different photoelectrochemical properties. The Cu2O polyhedron microcrystal with different crystal planes, which catalytic effect would be different as photocatalyst. In order to obtain efficiency catalyst for thermal decomposition of ammonium perchlorate (AP), Cu2O micro-particles with cubic, octahedral, truncated-octahedral and hollow opened sphere structures were synthesized in this part. Cu2O with different morphologies:cubes with six{100} faces, octahedral with eight{111} faces, truncated octahedral with six{100} faces and eight{111} faces and opening hollow micro spheres piled by the nanoparticles were synthesized through one-pot hydrothermal method, which is based on the reduction of Cu(II) with d-(+)-glucose in an alkali solvent. Morphology, crystal structure and specific surface area of final samples were characterized by using SEM, XRD, and BET, respectively. TG/DTA results show that the samples with different morphologies exhibit quite different catalytic activity in different stage of thermal decomposition of AP. Cu2O micro-octahedrons with{111} facets show better catalytic effect than cubes with only{100} facets, while the Cu2O opening hollow microspheres enhance the high-temperature exothermic decomposition of AP significantly, which offered some selection basis of catalysts in the thermal decomposition of AP. It can be concluded:(1) The{111} faces of octahedral with positive charge characteristic had better catalytic than{100} faces with electrically neutral characteristic;(2) The hollow spheres piled by nano particles can avoid reunion, improve their specific surface area and distribute uniformly, and then offered best catalytic properties.2. The preparation of Zn2+doped Cu2O micron polyhedrons and the study of the influence of doping on the optoelectronic properties of the materials.Doping transition metal oxides with different elements can enhance their optical, electrical, magnetic and catalytic properties. Zn2+dopping Cu2O was only discussed theoretically in the literature. In our work, we investigate the synthesis of Zn2+-Cu,O polyhedrons and their formation mechanism. The photoelectric properties were also studied. Zn2+-doped Cu2O polyhedrons with various crystal morphologies, from50-facet and26-facet, to8-facet, were synthesized via a mild, low temperature process based on the hydrothermal method. Addition of zinc salt to the reaction mixture might allow the introduction of Zn ions into the Cu2O crystal lattice, which is shown by X-ray photoelectron spectroscopy and energy dispersive spectrum. Doping of Cu2O crystals with Zn2+affects not only their morphologies but also significantly influences their optoelectronic properties. UV-visible and photoluminescence (PL) tests showed that the Zn2+-doped Cu2O system displays an increased band gap and enhanced PL properties. The open circuit potential-time (Ocp-t) method showed that a pure Cu2O crystal is an n-type semiconductor while the Zn-doped Cu2O crystal shows p-type characteristics.3. A simple and rapid method to prepare one dimensional CuO nanoribbons and3D CuO nanoflowers and the comparison of their pseudo capacitive performance.Recently, nano-scale materials have attracted much attention because of their unique properties. As an important low-cost and non-toxic transition metal oxide with a narrow band gap of-1.2eV, cupric oxide (CuO) has been exploited for lithium-ion batteries, and supercapacitors. In this work, one-dimensional CuO nanoribbons and three-dimensional CuO nanoflowers were synthesized via a facile, rapid, low-temperature, one-pot water bath method, in which the synthesis was performed in Cu(CH3COO)2/NaOH and aqueous/ethanol systems at70℃for15min. Control over the shape and dimensionality of the well-defined CuO single crystals was achieved simply by varying the order of addition of the reactive materials. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction were used to characterize the products. The formation mechanism in the in situ, rapid reaction was investigated. In Brunauer-Emmet-Teller and thermogravimetry measurements, the nanoribbons exhibited a higher specific surface area and higher adsorption capabilities than the nanoflowers. Using cyclic voltammetry, chronopotentiometry and EIS measurement for supercapacitor, it was shown that the nanoflowers electrodes had better performance than the nanoribbons electrodes. However, the nanoribbons/C electrodes had better performance than the nanoflowers/C electrodes at lower current density, but worse at higher current density, which revealed that nanoflowers had3D porous networks for electrolyte diffusion. While nanoribbons had smaller crystal grain size for full contact with the conductive skeleton, which were conducive to charge transfer and keeping structure unchanged.4. Morphology control of CuO nano array film based on copper substrate and the research of their lithium battery performance.CuO has a good application prospect in the negative electrode of lithium ion battery. The CuO nano array films on copper substrate can be used as cathode in lithium ion battery. The problem of agglomeration of nanometer powders can be avoided. In addition, during the production process, the adhesives do not need to be added into the electrodes, which reduce the internal resistance. In this part, by using a simple hydrothermal method, CuO nano array films with different morphologies were obtained from the same hot water kettle, under liquid and gas phase. By changing the concentration of reactants and the reaction temperature, the morphology can be controllable. Morphology and crystal structure of the samples were characterized with SEM, XRD, and their formation mechanism were investigated. To investigate the application of CuO nano arrays as the anode of lithium ion battery, the whole battery devices were prepared. We found that, the specific capacity can reach400-500mAh g-1under0.5C and reach300-400mAh g-1under0.1C. Their columbic efficiencies are about100%. Their capacities are less decreased after about100times cycle, especially; capacities of some films are increasing. |
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