留学美国签证研究计划模板大全.docx

1、留学美国签证研究计划模板大全留学美国签证研究计划模板大全（1）Descriptions of the research planTitle: Synthesis, Formation Mechanism, and Properties of Different Metal/Metal NanostructuresKeywords: Multi-Shell Nanostructures, Ionic Liquids, Electrochemistry, Multi-Functionality,Porous Metal Materials, Low-Dimensionality, Green Ch

2、emistry Objectives: This program is to develop a novel method for fabricating heterogeneous or alloyed different metal/metal low-dimensional nanostructures, for example, multi-shell or porous Ag-Au nanowires, nanorods, and nanocubes using an ionic liquid as both the solvent and shape-inducing templa

3、te. Synthesis of ionic liquids (ILs) with different alkyl chains and functional groups, as well as the formation of different metal/metal nanostructures with new properties are involved in this research plan. Alloyed or heterogeneous multi-shell nanostructures are generated by utilizing electrochemi

4、cal (electroless) deposition or a simple galvanic replacement reaction in ILs. By controlling the size, shape, composition, crystal structure and surface properties of these structures, it enables us not only to uncover their intrinsic properties, but exploit their formation mechanism in ILs media,

5、as well as their applications in catalysis, surface-enhanced Raman scattering (SERS), sensors, porous electrodes, etc. This green chemistry process also may be extended to synthesize other organic and inorganic nanostructures with novel properties, morphology and complex form. State-of-the-artMetal

6、nanostructures have numerous applications as nanoscale building blocks, templates, and components in chemical and biological sensors, as well as electronic/optical devices, due to their interesting optical, catalytic and electrical properties that depend strongly on both size and shape. Over the pas

7、t decade, impressive progress has been made towards the fairly good shape and size control of metal nanostructures 12. For noble metals, more emphasis is placed on tuning the novel shape-dependent properties of these nanostructures in contrast to the size-dependency. A variety of metallic building b

8、locks with unique properties have been synthesized including cubes 34, prisms 5, disks 6, and hollow nanostructures 7. Currently the interests migrate to the synthesis and application of more complex structures with different metals, such as multi-shell and heterogeneous nanostructures having new pr

9、operties89, coupling a conception for optimizing preparative strategies in an environmentally benign system10. Therefore, besides creating novel nanostructures with unique properties, a problem arising from the utilization of volatile or poisonous organic solvents and additives is of much concern in

10、 view of cleaner technology throughout both industry and academia.Most of the current shape selective synthesis of metal nanostructures that their optical properties are markedly affected by their shape and aspect ratio are centered either on a solid substrate by physical methods or in aqueous or or

11、ganic media through chemical procedures 2. For instance, complex and highly regular crystalline silver inukshuk architectures can be produced directly on a germanium surface through a simple galvanic displacement reaction that only three ingredients were required: silver nitrate, water, and germaniu

12、m 11. Despite these advancements, however, limited reports have been reported on how the particle morphology and dimensionality could be regulated by the utilization of ILs12.Recently, environmentally benign room-temperature ionic liquids (RTILs) have received increasing attention worldwide due to t

13、heir favorable properties including excellent thermal and chemical stability, good solubility characteristics, high ionic conductivity, negligible vapor pressure, nonflammability, relatively low viscosity, and a wide electrochemical window. This class of fluid materials contains complicated molecula

14、r interactions such as ionic interactions, hydrogen bonding, - interactions, and amphiphilic polarization, rendering various molecular structures from merely local orderness up to macroscopic thermo tropic or lyotropic liquid crystalline phases 13. These advantages make them actively being employed

15、as green solvents for organic chemical reactions, extraction and separation technologies, catalysis, solar cells, and electrochemical applications1415.In contrast to tremendous growth in R&D on application of ionic liquids to chemical processing, the use of RTILs in inorganic synthesis is still in i

16、ts infancy. There have been only a few reports on the shape-and-dimension controlled formation, by using RTILs, of hollow TiO2 microspheres 16 and nanowires of palladium 17, gold nanosheets 12, tellurium nanowires 18, flower-like ZnO nanostructures 19, and CuCl nanoplatelets 20. So far, alloyed meta

17、l structures, either spherical nanoparticles or nanocomposite films, have been generated in RTILs using electrochemical deposition of nanocrystalline metals such as Al-Fe, and Al-Mn alloys on different substrates 21. However, formation of multi-shell or hollow nanostructures by controlling both the

18、shape and dimension in RTILs has not yet appeared in literature, especially using an electrochemical approach. It is therefore proposed in this program that a new route to optically or catalytically tune the properties of complex metal/metal nanostructures through the control of shape anisotropy and

19、 surface morphology is established in RTILs using a green chemistry approach. The reasons we choose RTILs as reaction media are not only in the view of environment protection, but in the consideration of their diversiform molecular structures, which could be used as shape-inducing templates for the

20、synthesis of new nanostructures. It is very unlikely that ILs will entirely replace organic solvents or aqueous systems or gas phase processes for the fabrication of inorganic matter. Nevertheless, ionic liquids with different functional groups may provide a means to fabricate nanostructures that ar

21、e not otherwise available. The applicant has accumulated good backgrounds in shape-controlled synthesis and characterization of metal and semiconductor low-dimensional nanostructures with unique optical properties. A series of approaches have been used to fabricate Ag-SiO2, and Ag-TiO2 core-shell na

22、nostructures and Ag-SiO2-TiO2 nanocomposite films. During the Ph.D program, novel soft sol and polymer-assisted methods have been developed to form metal and semiconductor nanorods and wires, such as silver and gold nanowires, CdS and ZnS nanowires and rods, as well as anisotropic metal nanocrystals

23、, for example, silver nanoprisms, gold nanocubes, nanodisks, and so on 2223. At the same time, tuning the optical properties through the interaction of nanostructures with femtosecond laser pulses to control the size, shape or dimension in nanometer regime has also been investigated 24. As for the i

24、nstitution to which the applicant is applying and the group of Professor XXXXXXX, equipments including TEM, SEM, UV-Vis-NIR absorption spectrometer and other emission spectrometer (static, time-resolved and temperature dependent), as well as the groups excellent research experience in semiconductor

25、and metal nanomaterials 2526 provide a sound foundation for the implementation of this research plan, probably resulting in not only a better understanding of the utilization of RTILs in nanochemistry and electrochemistry, but creating new nanostructures, such as microporous Ag/Au multi-shell nanowi

26、res with promising applications in SERS, catalysis, etc.A multidisciplinary approach and the planned activitiesA multidisciplinary approach is designed in this proposal through integrating organic synthesis, electrochemistry, materials science and optoelectronics, aiming to fabricate different metal

27、/metal multi-shell heterogeneous nanostructures including nanocubes, nanorings, nanoplates, nanowires and nanotubes. This research plan covers three aspects: The first one is to create novel structures through the reduction of different metal precursors in RTILs using reducing agents or electrosynth

28、etic processes. The second is to produce porous low dimensional metal nanostructures by etching with specific solutions (e.g. concentrated ammonia or hydrochloric acid) or using galvanic displacement reaction and electrochemical anodization. The third is to investigate the formation mechanism and pr

29、operties of these nanomaterials.1. Synthesis of metal nanostructures with tailored morphology2. Formation of porous low dimensional nanostructures.3. Properties of different metal/metal nanostructures.4. A possible extension of this research planAnother important direction is to fabricate magnetic/s

30、emiconducting core-shell nanocrystals, such as Fe3O4/CdSe, or dye molecule complexed rare earth metals to form Gd(BPy)/CdSe using RTILs as reaction media. These nanocrystals containing both fluorescence and magnetic resonance embedded in silica nanoparticles can be used as probes for the study of bi

31、ological materials, especially in bio-imaging. The magnetic/semiconducting core-shell complex nanocrystals offer distinct advantages over conventional dye-molecules, magnetic resonance imaging (MRI), and simplex semiconductor nanocrystals not only in that they emit multiple colors of light and can b

32、e used to label and measure several biological markers simultaneously, but in the capability to target molecules with a good spatial resolution.Time schedule for the planMay 1, 2006-July 1, 2006Two months German learning in a Goethe InstituteJuly 1, 2006-Oct. 31, 20061. Discussion on the detailed research plan and the preparation of materials2. Synthesis and characterization of low-dimensional nanostructures in RTILs3. Publishing 1 papers4. Attending one international convention on nanostructures and applicationsNov. 1, 2007-Mar. 31, 20071. Further improvement of the optical and cat