|
Refers to a specific arrangement by the sub-micron level (meso-) or nanoscale (nano-) monodisperse colloidal microspheres after two-dimensional or three-dimensional ordered colloidal crystals (colloid crystal), similar to the crystal structure of the system. Due to their structural characteristics, have a wide range of applications in many fields. The monodisperse silica narrow size distribution by self-assembly prepared colloidal crystals, used in paints, pharmaceuticals and other aspects. Ultrafine nickel oxide powder as a nano-metal materials, and have a wide range of applications in many fields, can be used as catalysts, battery materials, carbide binder. The core-shell structural material because of its composition, size, different structures can be obtained a multifunctional material. Can reduce the cost of the catalyst through the surface of the silica-coated nickel hydroxide, also can increase the infrared absorption of the catalyst, and to broaden the scope and practical value of the use of a catalyst. In the surface of the nickel hydroxide coated silica, can greatly improve the toughness of the material, abrasion resistance and corrosion resistance. In this paper, based on extensive literature research, mainly the following aspects of the work. Using of different purity TEOS monodisperse silica particles, transmission electron microscopy, dynamic light scattering characterization of raw material purity of the product monodisperse impact, to further improve nucleation mechanism silica on this basis, and guidance to prepare monodisperse silica; assembled by the the vertical sedimentation method of synthetic silica, and the assembled effect was characterized by scanning electron microscopy, and assembly defects were analyzed. Triton X-100, n-heptyl alkoxy, n-hexyl alcohol as a system, Microemulsion Method Preparation of monodisperse hydroxide nickel, of different conditions on the size of the nanoparticles are discussed: (1) micro-emulsion of the composition on the particle size impact, but are not major factors; (2) With the increase of the concentration of sodium hydroxide, particles gradually decreased in size (3) In the nickel sulfate concentration is less than 0.05mol ยท L-1, the particle size of nickel from sulfate Concentration, when this concentration is exceeded, with the increasing concentration of the particle size increases. The results show that: the formation and growth of the particles, not only with the microemulsion composition, the sodium hydroxide concentration, the concentration of nickel sulfate, also related to the reaction rate. Respectively ligand prepared by precipitation of the two kinds of core-shell structure, and by transmission electron microscopy (TEM), X-ray diffraction (XRD) characterization showed that: with this method the surface of the silica-coated nickel obtained hydroxide nanomaterials uniformly coated, does not appear not coated with silica particles; better covering effect in the surface of the nickel hydroxide coated silica, but monodisperse particles is not good, so the reaction conditions to be further explored .
|