Noble metallic nanoparticles

Noble metal nanoparticles dispersed in insulating matrices have attracted the interest of many researchers fromboth applied and theoretical points of view [34]. The incorporation of metallic nanoparticles into easily processable polymer matrices offers a pathway for better exploitation of their characteristic optical, electronic and catalytic properties. On the other hand, the host polymers can influence the growth and spatial arrangement of the nanoparticles during the in situ synthesis, which makes them convenient templates for the preparation of nanoparticles of different morphologies. Furthermore, by selecting the polymer with certain favorable properties such as biocompatibiHty [35], conductivity [36] or photoluminescence [37], it is possible to obtain the nanocomposite materials for various technological purposes. 

Porter LA, Choi HC, Ribbe AE, Buriak JM (2002) Controlled electroless deposition of noble metal nanoparticle films on Germanium surfaces. Nano Lett 2 1067-1071... 

In the past five years, the use of nanoparticles in this active research area has received increased attention since some homogeneous catalysts have been shown to be nanoheterogeneous [24-26]. Today, soluble noble metal nanoparticles are considered as reference in monocyclic arene catalytic hydrogenation under mild conditions and several stabilized systems have been reported [27,28]. 

ROsch N (1999) A Critical Assessment of Density Functional Theory with Regard to Applications in Organometallic Chemistry. 4 109-163 Roucoux A (2005) Stabilized Noble Metal Nanoparticles An Unavoidable Family of Catalysts for Arene Derivative Hydrogenation. 16 261-279... 

Stabilized Noble Metal Nanoparticles An Unavoidable Family of Catalysts for Arene Derivative Hydrogenation... 

To summarize, we have shown here that enhanced electric-field distribution in metal nanoparticle assemblies can be visualized on the nanoscale by a near-field two-photon excitation imaging method. By combining this method and near-field Raman imaging, we have clearly demonstrated that hot spots in noble metal nanoparticle assemblies make a major contribution to surface enhanced Raman scattering. 

In this chapter, we have provided an overview of near-field imaging and spectroscopy of noble metal nanoparticles and assemblies. We have shown that plasmon-mode wavefunctions and enhanced optical fields of nanoparticle systems can be visualized. The basic knowledge about localized electric fields induced by the plasmons may lead to new innovative research areas beyond the conventional scope of materials. 

The size of metal nanoparticles plays also a role in a quite different field of nanoscience the interaction with biosystems with nanoparticles in general, here especially with metal nanoparticles. Chapter 4 will deal with some very recent aspects considering the interaction of noble metal nanoparticles with biomolecules and living cells. 

There exist numerous reports on the interaction of noble metal nanoparticles, especially those of gold, with DNA. The reason for this intense work in most cases is the use of gold nanoparticles for the analysis of nucleic acids, or proteins. In any case, the interactions between the two... 

Pt/Ru bimetallic nanoparticles. In the case of dye-sensitized photochemical water splitters, to which much attention has been received recently, noble metal nanoparticles are often used for the active centers to produce hydrogen gas from water. Bimetallic nanoparticles will be easily replaced by these metal nanoparticles for the sake of saving resources. 

Interpretation of the Electronic Structure of Transition and Noble Metal Nanoparticles... 

This alcohol reduction method is applied to the control of size and composition of not only the noble metal/noble metal [7] but the 3d-transition metal/noble metal nanoparticles [8] like magnetic FePt nanoparticles. 

Takagi E, Mizukoshi Y, Oshima R, Nagata Y, Bandow H, Maeda Y (2001) Sonochemical preparation of noble metal nanoparticles in the presence of various surfactants. Stud Surf Sci Catal 132 335-338... 

Mizukozhi Y, Makise Y, Shuto T, Hu J, Tominaga A, Shrionita S, Tanabe S (2007) Immobilization of noble metal nanoparticles on the surface of Ti02 by the sonochemical method photocatalytic production of hydrogen from an aqueous solution of ethanol. Ultrason Sonochem 14 387-392... 

Facile in situ synthesis of noble metal nanoparticles in porous cellulose fibers. Chemistry of Materials, 15, 4401 1406. 

Similarly, Kou et al. published the synthesis of PVP-stabilized noble-metal nanoparticles in ionic liquids BMI PF6 at room temperature [76]. The metal nanoparticles (Pt, Pd, Rh) were produced by reduction of the corresponding metal halide salts in the presence of PVP into a refluxing ethanol-water solution. After evaporation to dryness the residue was redissolved in methanol and the solution added to the ionic liquid. The methanol was then removed by evaporation to give the ionic liquid-immobilized nanoparticles. These nanoparticles were very stable. TEM ob-... 

Table 9.10 Hydrogenation of alkenes catalyzed by PVP-stabilized noble-metal nanoparticles in [BMI][PF6]. (Adapted from [76])...

Scheme 9.9 Total hydrogenation of monocyclic arene compounds by various zerovalent noble-metal nanoparticles.

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