Metal nanoscale templates

While the use of metal oxide nanoparticles is dependent on their synthesis and subsequent magnetic or ceramic properties, size homogeneity is also necessary because the nanoparticles properties are related directly to their size. Natural templates, such as butterfly scales, peptide nanorings and bacterial or protein cages, can be tuned to induce narrow size distributions that have yet to be seen within an industrial setting. These chemically engineered systems have been proven to serve as viable nanoscale templates for the constrained biomimetic synthesis of higher-ordered metal oxide nanoparticles with unique properties specific to their synthesis. 

Seo, S. Ye, T. Borguet, E. Electrochemical nanoscale templating Laterally self-aligned growth of organic/metal nanostructures. Langmuir 2012, 28, 17537-17544. 

Oxide surfaces, and in particular oxide films, are versatile substrates for the preparation of model catalysts. Quite a few of these systems show nanoscale reconstructions, which can be employed as templates for the growth of ordered model catalysts of reduced complexity. In order to efficiently control the growth of nanostructured metal particle arrays, two conditions have to be met. First, the template must provide sites of high interaction energy that trap the deposited metals. Second, the kinetics of the growth process must be carefully controlled by choosing... 

Price, R.R., Dressick, W.J. and Singh, A. (2003) Fabrication of nanoscale metallic spirals using phospholipid microtubule organizational templates. Journal of the American Chemical Society, 125, 11259-11263. 

Surface-Mediated Nanoscale Fabrication of Metal Particles and Wires Using Mesoporous Silica Templates and Their Shape/ Size Dependency in Catalysis... 

Figure 15.1 Ordered nanoscale structures of mesoporous materials such as FSM-16 and HMM-1 (Et-HMM-1) as the silica and organosilica templates for surface-mediated synthesis of metal/alloy nanowires and nanoparticles.

This chapter deals with the selective preparation, TEM/EXAFS/XPS characterization and catalysis of mono- and bimetallic nanowires and nanoparticles highly ordered in silica FSM-16, organosilica HMM-1 and mesoporous silica thin films. The mechanism of nanowire formation is discussed with the specific surface-mediated reactions of metal precursors in the restraint of nanoscale void space of mesoporous silica templates. The unique catalytic performances of nanowires and particles occluded in mesoporous cavities are also reviewed in terms of their shape and size dependency in catalysis as well as their unique electronic and magnetic properties for the device application. 

It has been previously reported [21, 22] that metal colloids are formed by radiochemical reactions in water/alcohol solutions, in which the reduction of metal salts takes place by solvated electrons and free radicals produced under UV or y-ray irradiation. Ichikawa et al. have applied this photoreduction method to the surface-mediated reaction of metallic ions and succeeded in synthesizing metal/aUoy nanowires in the constrained cavities of mesoporous supports such as FSM-16 and MCM-41 [18-20, 23-25]. The adsorbed water and alcohol work not only as solvents in the nanoscale silica void space but also as a source of reducing species for metallic ions to metals under UV-vis and y-ray [11, 18, 19] irradiation. The results indicate the dense formation of Pt nanowires inside the charmels of mesoporous supports, such as FSM-16, which act as the templates. In fact, no any Pt wire is observed on the external surface of FSM-16 or amorphous silica surface. Short wires, 10 nm long, are also observed as a minor species in the samples in the initial stage of UV and y-ray irradiation. 

We have reviewed the state of the art of the synthesis and applications of metal/ alloy nanowires and nanoparticles by surface-mediated fabrication using different mesoporous silica templates. New nanoscale materials are appearing one after another by the use of many kinds of mesoporous materials as templates, and we are facing a rapid advance of this research field. So far, many studies have focused... 

Indeed, substantial progress in the application of DNA as a template for the bottom-up construction of metallic NPs or nanowire circuitry, and the assembly of nanoscale miniaturized devices, was demonstrated in the past decade.90... 

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