Metal nanoparticles, immobilization

Originally, the effect of charge state of nanostructures on their catalytic activity was recognized from analysis of the experimental data on the catalytic properties of metallic nanoparticles immobilized in the matrix of a poly-paraxylylene polymer [13-15,24]. It was found that the dependence of the catalytic activity (and, in some cases, of the selectivity) of copper, palladium, and iron nanoparticles on the metal content of these structures has a maximum. This maximum exists not only for the specific (related to unit weight) activity, but also for the absolute activity. More specifically, for copper and... 

Fig. 3 Formation of metal nanoparticles in the PS-PNIPA core-shell system. The crosslinked PNIPA chains absorb metal ions step 1) which are reduced to produce corresponding metal nanoparticles immobilized in the thermosensitive network step 2)...

Figure 10 shows the values of the apparent rate constant kapp as a function of theoretical specific surface area of metal nanoparticles immobilized in different carrier systems. As shown in Fig. 10, a strictly linear relationship between kapp and the surface of the metal nanoparticles can be observed. Figure 10 demonstrates that Pt and Pd nanoparticles exhibit higher catalytic activity than AgNPs. Table 1... 

Fig. 14 Catalytic oxidation of benzyl alcohol in the presence of metal nanoparticles immobilized in thermosensitive core-shell microgels at different temperatures. At lower temperatures (T < 32°C) the microgel network is hydrophilic and swollen in water, whereas at high temperatures (T > 32°C), the network shrinks and becomes hydrophobic. Thus, microgel particles embedding the metal catalyst will move to the oil phase, which will be favorable for the uptake of hydrophobic benzyl alcohol into the metal-microgel composite. Therefore, the catalytic activity of the metal-microgel composites will be affected both by the volume transition and the polarity change of the microgel [29]...

SERS from Metal Nanoparticles Immobilized on Optically Trapped Beads... 

Recently, there have been many reports on the effects of CD on metal catalytic systems. A potentially interesting approach for the modification of catalytic systems based on metal complexes, such as Zn, Mo, Fe, In, Sn, Pd or Ru, involves the use of CD as a protective agent. There are many reports on the interaction between CDs and metallic nanoparticles.Immobilized CD on Pd nanoparticles was employed as an efficient mediator in aqueous biphasic hydrogenation reactions (Figure 4.6a,b). ... 

Wire-shaped growth of nanostructured PPy with diameter <10 nm, has been obtained by electropolymerization at naturally occurring step defects and artificially formed pit defects of HOPG, in a template assisted electropolymerization where the size of the nanostmctures could be controlled by limiting the pyrrole polymerization time at anodic potentials [242], Electrochemical polymerization of pyrrole within the confines of anodized alumina templates and subsequent metal nanoparticles immobilization on the surface of polymer pillars has been used to make surfaces that show roughness on two independently controllable levels sub-microscopic roughness from polymer pillar dimensions and nanoscopic roughness from the appropriate size selection of metal NPs [243],... 

Scheme 15.42. The approach for preparation of dendron-stabilized metal nanoparticles immobilized on solid support.

Deposition of metal nanoparticles (immobilization of functionalized species [104], in sifw synthesis [105-107], electrochemical etching [108], self-assembling of colloids [109], sputter coating [110]). 

Figure 5.3 A typical configuration for nanoparticle-enhanced SPR detection. First, the metal film captures the analyte molecules, which in turn capture metallic nanoparticles immobilized with complementary molecules or functional groups to the analyte molecules.

Wet Preparation of Metal Nanoparticles and their Immobilization on Silicon Substrates... 

Wet preparation of metal nanoparticles and their covalent immobilization onto silicon surface has been surveyed in this manuscript. Thiol-metal interaction can be widely used in order to functionalize the surface of metal nanoparticles by SAM formation. Various thiol molecules have been used for this purpose. The obtained functionalized particles can be purified to avoid the effect of unbounded molecules. On the other hand, hydrogen-terminated silicon surface is a good substrate to be covered by Si-C covalently bonded monolayer and can be functionalized readily by this link formation. Nanomaterials, such as biomolecules or nanoparticles, can be immobilized onto silicon surface by applying this monolayer formation system. 

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... 

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-... 

The immobilization of metal nanoparticles with a water-soluble polymeric material such as PVP has also been described. The groups of Choukroun and Chaudret have described the hydrogenation of benzene in a biphasic mixture with PVP-protected native Rh nanoparticles synthesized from the organometal-... 

Fig. 3. Schematic illustration of the synthesis of metal nanoparticles within dendrimer templates. The composites are prepared by mixing of the dendrimer and metal ion, and subsequent chemical reduction. These materials can be immobilized on electrode surfaces where they serve as electrocatalysts or dissolved in essentially any solvent (after appropriate end-group functionalization) as homogeneous catalysts for hydrogenation and other reactions...

RuCNC heterobi metal lie ruthenium/cobalt nanoparticle immobilized on charcoal. 2-Pyridylmethyl formate is used. 

The development of assemblies of inorganic materials with biomolecules has emerged as a novel approach to the controlled fabrication of functionalized nanostructures and networks.5 The practice of DNA sequence detection is especially relevant for forensic sciences, food safety, genetics and other fields.6 The immobilization of single strand DNA probes onto solid materials such as noble metal nanoparticles has proved to be the basis for a multitude of quite different nanobiotech-nological and biomedical applications, including the DNA driven assembly of nanoparticles and biosensors.5-11... 

These were prepared by tethering Rh and Pt complexes to silica-supported metal catalysts (metal = Pd, Ni, Ru, Au). The catalysts are very active in the hydrogenation of benzene derivatives to the corresponding substituted cyclohexanes under mild conditions. The activities are higher than those of the separate homogeneous complexes, complexes just tethered to silica, or the silica-supported heterogeneous catalysts. When the sol-gel-entrapped [Rh2Co2(CO)12] complex was heat-treated at 100°C, immobilized metallic nanoparticles were formed.425 The catalyst thus prepared efficiently catalyzed substituted benzene derivatives. 

Metal nanoparticles have also been included into MIPs. Such particles can be used, for example, as nanoantennae for the enhancement of electromagnetic waves (plasmonic enhancement). It has been shown by He et al. [122] that a thin layer (20-120 nm) of testosterone-imprinted silica could be synthesized around 350 nm silver particles in a controlled way. The composite material showed specific binding of the testosterone target. Matsui et al. [123] reported a molecularly imprinted polymer with immobilized Au nanoparticles as a sensing material for spectrometry. The sensing mechanism is based on the variable proximity of the Au nanoparticles... 

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