| Nanocrystals are refered to the crystals with at least one dimension between1to100nanometers. They also are characterized by a single-domain crystalline lattice, without the complicating presence of grain boundaries. Interest in nanocrystals has been growing steadily due to their unique position as a bridge between atoms and bulk solids as well as their fascination properties and potential applications. The ability to generate such minuscule scrystals is central to advances in many areas of modern science and technology. In principle, the electron confinement by a nanocrystal provides the most powerful mens to manipulate the electronic, optical and magnetic properties of a solid material. Copper is an abundant eletemnt, and copper-based materials have attracted many scientists’attentions. For example, CuS is a p-type semiconductor with a band gap of1.2-2.0eV and has a lot of applications like solar battery, solar absorber, nanoswith, thermolelectrity material, superconduntivity material, and gas sensor. Copper nanowires are not only applicated in connecting wires of nanodevices, but also used for transperant conducting film. Cu/C composite material is a better glucose oxidation electrocatalyst from an economic point of view. Copper vanadium oxide is a potential implantable cardiac defibrillator material and can provide high energy density, high power ability and stability. CuO is a p-type semiconductor with a band gap of1.2eV, and can be used as high-temperatrue superconductivity, giant magnetoresistance materials, lithium-ion battery material, gas and chemical sensor. In this dissertation, we synthsized a lot of Cu-based nanomaterials by amine-assited hydrothermal method, including CuS hexagonal bifrustum, Cu nanowires, Cu/C hollow spheres, carbon spheres immobilized with monodispersed Cu nanoparticles, copper vanadium oxide followers and porous CuO ellipses, characterized the products, investigated the properties, and discussed the synthsis parameters and growth mechanisms. The main research contents are as follows:(1) The hexagonal bifrustum-shaped copper sulfide (CuS) nanocrystals were selectively and facilely synthesized by a hydrothermal method for the first time at120℃. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, ultraviolet-visible spectroscopy, and photoluminescence spectroscopy. Tetradecylamine (TDA), as an effective capping agent, was found to be critical for this special shape. And the results revealed that the CuS nanocrystal evolved from hexagonal plate to hexagonal bifrustum and finally to hexagonal bipyramid as the heating time increased. The ultraviolet-visible absorption spectrum showed that these CuS hexagonal bifrustum nanocrystals exhibited strong absorption in the near-infrared region and had a potential application for photothermal therapy and photocatalysis.(2) Copper (Cu) nanowires are inexpensive conducting nanomaterials intensively explored for. transparent conducting electrodes and other applications. Here Cu nanowires with approximately40nm in diameter and a few hundreds of micrometers in length were selectively and facilely synthesized by a tetradecylamine(TDA)-assisted hydrothermal method. The Cu nanowires were highly flexible and were not oxidized by oxygen in air because of TDA’s effective coating on the Cu nanowires. Moreover, the Cu nanowires tended to self-assemble into close-packed bundles due to hydrophobic-hydrophobic interactions between alkyl chains of TDA.(3) Novel Cu-carbon hybrid hollow spheres (HSs) are easily prepared by a combination of hydrothermal carbonization (HTC) and emulsion template method for the first time. The HSs have an average diameter of3.5μm and a shell thickness of about70nm. The HSs consist of a matrix of hydrothermal carbon, in which Cu nanoparticles of several nanometers in size are imbedded, and exhibit a well-defined shape, a relatively uniform size and high flexibility. With regard to the formation mechanism, trioctylamine (TOA) droplet in the oil-in-water (W/O) emulsion plays the role of a template. Under hydrothermal conditions, TOA in the droplet and Cu2+outside the droplet form the Cu-amine complex, which aggregates at the interface and is then reduced to form Cu nanoparticles by ascorbic acid (VC), and HTC of VC to hydrothermal carbon occurs at the interface. By changing the carbon source into glucose the size of HSs can be tuned down to1μm and the bowl-like hollow structure can be obtained by increasing reaction time, indicating the flexibility of this approach. Due to the special structure of these HSs, they can be used as a new ultrasound contrast agent or a template for porous CuO HSs.(4) Carbon spheres (CSs) immobilized with monodispersed Cu nanoparticles were synthesized by a non-surfactant-assisted method. In this protocol, the biomass (ascorbic acid) transformed into the spheres of hydrothermal carbon through hydrothermal carbonization, and copper chlorite was reduced to Cu nanoparticles, which were in situ deposited on the spheres. No excess surfactant or capping reagent was necessary, which made the surface of the as-prepared nanoparticles very clean. In the following annealing, the spheres of hydrothermal carbon converted into CSs and the size of Cu nanoparticles could be tuned from several nanometers to dozens of nanometers by changing the annealing temperature only. This hybrid composite exhibited excellent catalytic activity for oxidation of glucose and could be employed as a rapid and inexpensive glucose sensor.(5) Copper vanadate oxides have a wide variety of crystalline phases such as CUV2O6, Cu3V2O8, Cu0.95V2O5, Cu0.4V2O5, Cu2V2O7and so on, and has been used in catalytic and battery fields. Here, for the first time, we presented a new hexylamine-assisted method to prepare hierarchical Cu4V2.15O9.38superstructure assembled by single-crystalline nanorods. The results showed that the produce of Cu4V2.15O9.38was highly related to hexylamine and that by controlling the amount of copper source the Cu4V2.15O9.38superstructure was transformed via the intermediate Cu3(OH)2V2O7·2H2O. Then, we studied its electrochemistry properties in glucose electrocatalytic oxidation and primary lithium ion battery. The sensitivity of the modified electrode to glucose was estimated to be175.8μA mM-1cm-2, and the detection range is from0to3mM glucose solution, and the detection limit was less than0.1mM. The material had a large discharge capacity of301mA h g-1at5mA g-1, thus making it an interesting candidate for primary lithium ion batteries.(6) The common method to prepare CuO is mixing copper salt solution and basic solution and producing Cu(OH)2, which then convert to CuO. Here, we used a new way to synthesize CuO, where NH4VO3is added to change the reaction pathes. Copper salt firstly reacts with NH4VO3to form an intermiediate copper vanadium oxide phase, which then transforms into CuO. The change of the amount of NH4VO3can tune the oriented attachment growth mechanism of CuO and obtain porous CuO ellipses. The ellipses are single-crystallined and the submits are nanorods with diameter of dozends of nanometers. The porous structure is stable and not broken at200℃. Compared with compact structure, porous structure exhibts more exposed surface, better electric conductivity and ion diffusion ability, better ability to compensate the stress in the material, and is a better catalyst or battery material. |
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