| Nanopowders are powders with novel physical and chemical properties and characteristic scale of which is no more than 100 nanometers. One of the very basic results of the physics and chemistry of solids is the insight that properties of solids depend on the microstructure, i.e. the chemical composition, the arrangement of the atoms (the atomic structure) and the size of a solid in one, two or three dimensions. In other words, if one changes one or several of these parameters, the properties of a solid vary. Owing to the extremely small dimensions, nanometer materials are structurally characterized by a large volume fraction of grain boundaries or interphase boundaries, which exhibit some unique structural characteristics and novel properties with respect to the conventional coarsegrained polycrystalline materials. As a part of new materials, nanostructured materials are playing an important role in many fields, such as information, manufacturing, biotechnology and agriculture etc. In this paper, we have developed several methods for preparation of Ni, CeOi and Co/Ni nanopowders, and have studied their application in catalytic dehydrogenation, Ion-selective electrodes and industrialize amplification of nickel nanopowder.PART I. ReviewChapter 1.In this chapter, we described some basic properties of nanoparticle, such as quantum-size effect, surface effect, small-size effect, macro-quantum tunnel effect and so on. In addition, the tendency of nanopowder's applications in eight fields was also outlooked. Looking ahead, major innovation can be expected in the preparation of high performance nanophase coatings and consolidate parts.Chapter 2.Powder synthesis techniques fall into three broad categories: (1) precipitation from a salt solution, (2) condensation from the vapor phase, and (3) high-energy milling. These include: laser ablation, microwave plasma synthesis, precipitation from either metalorganic or aqueous salt solution, spray pyrolysis and spray conversion processing, and gas condensation using either an evaporative source or chemical precursor. In this chapter, we have reviewed many kinds of techniques and recent progress in preparing nanometerpowders including the principles, varieties and characteristics of those three ways. PART II. ExperimentsChapter 3.Nanocrystalline nickel powders were prepared from aqueous solution by reducing their corresponding metal salts under suitable conditions. The experimental conditions including the types and concentration of protective agents, feeding order and the pH of the solution that influence the average particle size was studied in detail. X-ray powder diffraction patterns show that the nickel powder is cubic crystallite. The average particle size of the ultrafine nickel powder is 50nm. In addition, we also studied the effect of particle size in liquid phase dehydrogenation of 2-butanol. The results show that the smaller particle size is favored of increasing catalytic activity.Chapter 4.Ni/Co bimetallic nano-cluters have been prepared from aqueous solution by reducing their corresponding metal salts under suitable conditions. The experimental conditions including the types and concentration of protective agents, feeding order and the pH of the solution that influence the average particle size have been studied in detail. Transmission electron microscopy indicates that the shape of those bimetallic nanoclusters particles is spheroid. The alloy structure has been shown by X-ray powder diffraction. X-ray photoelectron spectroscopic data have confirmed that the nickel and cobalt in the bimetallic nanoclusters is in the zero-valence state and alloy state, respectively.Chapter 5.CeOi nanoparticles of average diameter about 30 nm were prepared by sol-gel method in lower temperature. The gel, transformed form the aqueous solution of metal nitrate and citric, can be comburented completely in lower temperature. The redox behavior and crystallization process of the dried gels were studied by thermogravimentric analysis and infrared spect...
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