Fabrication Of Ag-Au Bimetal And Large-sized Porous Au Nanostructures And Studying Of Their Properties

Noble metals, including gold, silver, platinum, palladium, ruthenium, rhodium, osmium and iridium, are an important part of non-ferrous metals. Noble metals have widely applications in industrial, and their deep-processing products are used in these industries covering almost all sectors of the electronics, chemicals, Pharmaceuticals, machinery, energy, metallurgy, ceramics and transportation. The concept of noble nanomaterials is that using nanotechnology for development and production of noble metal products to get new nanoscale materials about100nm (or containing nano-phase with the appropriate size). These new materials are very different with the traditional noble materials in the properties of optical, electrical, acoustic, magnetic, catalytic and mechanical. Based on their special physical and chemical properties, noble nanometals become an important part of the nanomaterials.Due to the superiority of noble metal nanoparticles in performances of optical, electrical and catalytic, synthesis and application of noble metal nanostructures have been widely studied. The adjustment of performances is derived from the controlled synthesis of noble metal component, size, morphology and structure. Nowadays, research in this area has got different shapes of monometallic nanostructures such as wires, rods, spheres, plates and cubes. Besides, for the synthesis of bimetal, synergistic effects between specific physical and chemical properties upon bimetallic nanostructures have enabled to combinate the properties associated with two different metals to exhibit superior performance. In addition, some special nanostructures, such as hollow, porous, frame and so on, have large surface area. Because of their higher surface energy, reaction could be carried out at a lower temperature and reduced the occurrence of side-reaction; it can improve the reaction activity. Thereby, the main content of this paper is synthesis and application of noble metals nanostructures.Firstly, by study of theory on the synthesis of Au and Ag, it is found that the close lattice constant of Ag and Au could be considered as reliable evidence to produce bimetallic nanostructures by co-reduction at room temperature. During the process of synthesis, component-depended performance is more evident than component-depended shape. The study on enzyme-free H2O2sensor makes us know that the change depending on component is significantly. Besides, it has been explain component-depended performance by using a reasonable mechanism.Secondly, with the advantages of the large surface area and high activity, small-sized (about10nm) exhibit superior performances, but unstable occurrence can not be avoided. Large-sized one is relatively stable, but it can not display the capability of the internal component. Now, by "re-growth etching" technology, large-sized porous Au nanostructures have been produce from Au-Ag bimetal that we choose a special etchant "Au1". We successful obtain large-sized porous Au nanostructures with the size range from300nm to500nm. While maintaining the relative stability of the structure, they all retain the performance characteristics of small-sized nanoparticles. Taking the typical nitrophenol catalytic reduction as model, study found that their performances of large-sized porous Au nanostructures refer to the size and number of pore.