Ni, Co, Water, Alcohol, System Synthesis Of Metal Nanomaterials,

In this dissertation, several solution-based chemical synthetic routes such as hydrothermal, refluxing and other technique were developed for the fabrications of metallic Ni and Co nanostructured crystals. In the routes, some specific chelate extracting agent and characteristic reagent were extended to the formation of above nanocrystals with various structures and morphologies. These structures and morphologies were characterized, and the properties relevant to their structures and shapes were considerably investigated. The main points are summarized as follows:1.Solution route to hierarchical nanostructures were developed. A novel hierarchical orange-like Ni nanostructure was grown through a complex-surfactant-assisted hydrothermal process. The magnetic coercivity Hc of the as-prepared orange-like Ni nanostructures is 120 Oe.2. The galvanic replacement reaction between a metal and another metallic ions solution were demonstrated to metallic nanocrystals. Nickel nanotubes were synthesized using reduction of nickel chloride by metallic zinc in aqueous solution at room temperture. The inner diameter and wall thickness of these nickel nanotubes are respectively, 30-150 run and 5-20 nm. The magnetic coercivity Hc of the as-prepared Ni nanotubes is about 195 Oe. When replacing water with ethanol as solvents, Zn-doped Ni nanotubes with wall thickness 10-20 nm and inner diameter 100-200 nm were synthesized. The magnetic coercivity Hc of the as-prepared products was investigated to be 515.6 Oe. Using as-prepared nickel nanotubes as reducing agent, Ag dendritic nanostructures were obtained via a mild hydrothermal reaction. Other nickel materials used as reductant to Ag nanomaterials were also studied. When using Raney Ni as reductant, novel skeletal silver with netlike structures were synthesized via a seed-mediated solution route.