Nanoparticles platinum

These P-CD/adamantyl pseudorotaxane-terminated dendrimers can be used as nanoreactors in the preparation of gold and platinum nanoparticles in water... 

Fig. 6 TEM micrograph of hexadecylamine stabilized platinum nanoparticles showing the formation of nanowires...

Thiols are known to be excellent hgands for the stabilization of gold and platinum nanoparticles. In this respect, we did not observe any Iluxional behavior [31,52] in solution NMR experiments for thiols coordinated to the surface of noble metal particles (Fig. 8). However, in the case of rutheniiun, we foimd the slow catalytic formation of alkyl disulfides [31]. After exclud-... 

The coordination of ligands at the surface of metal nanoparticles has to influence the reactivity of these particles. However, only a few examples of asymmetric heterogeneous catalysis have been reported, the most popular ones using a platinum cinchonidine system [65,66]. In order to demonstrate the directing effect of asymmetric ligands, we have studied their coordination on ruthenium, palladium, and platinum nanoparticles and the influence of their presence on selected catalytic transformations. 

Dendrimer-protected colloids are capable of adsorbing carbon monoxide while suspended in solution, but upon removal from solution and support on a high surface area metal oxide, CO adsorption was nil presumably due to the collapse of the dendrimer [25]. It is proposed that a similar phenomena occurs on PVP-protected Pt colloids because removal of solvent molecules from the void space in between polymer chains most likely causes them to collapse on each other. Titration of the exposed surface area of colloid solution PVP-protected platinum nanoparticles demonstrated 50% of the total metal surface area was available for reaction, and this exposed area was present as... 

Electrodeposition of metals can be performed under different electrochemical modes. In the work mentioned in Ref. [18], it was performed in potentiostatic mode. The potential value for formation of platinum nanoparticles is —25 mV vs. SCE the deposition is performed from 2.5 mM solution of H2[PtCl6] in 50 mM KCl. The size of nanoparticles formed depends on the reduction charge. Continuous monitoring of the charge in potentiostatic mode is provided by different potentiostats, for example, by Autolab-PG-stat (EcoChemie, The Netherlands). Conditions for deposition of other metals should be selected according to their electrochemical properties. 

In the early work on the thermolysis of metal complexes for the synthesis of metal nanoparticles, the precursor carbonyl complex of transition metals, e.g., Co2(CO)8, in organic solvent functions as a metal source of nanoparticles and thermally decomposes in the presence of various polymers to afford polymer-protected metal nanoparticles under relatively mild conditions [1-3]. Particle sizes depend on the kind of polymers, ranging from 5 to >100 nm. The particle size distribution sometimes became wide. Other cobalt, iron [4], nickel [5], rhodium, iridium, rutheniuim, osmium, palladium, and platinum nanoparticles stabilized by polymers have been prepared by similar thermolysis procedures. Besides carbonyl complexes, palladium acetate, palladium acetylacetonate, and platinum acetylac-etonate were also used as a precursor complex in organic solvents like methyl-wo-butylketone [6-9]. These results proposed facile preparative method of metal nanoparticles. However, it may be considered that the size-regulated preparation of metal nanoparticles by thermolysis procedure should be conducted under the limited condition. 

These types of complexes, [Ag(Ci3H27COO)(PPh3)j and [Pt (Ci3H27COO)2(PPh3)2j, are also chosen as the precursors for the solvent-free controlled thermolysis to produce silver nanoparticles with average size 5.7 nm and platinum nanoparticles with average size 2.7 nm, respectively [13]. 

NMR measurements are very useful to understand the properties of the stabilizing reagents of metal nanoparticles. Author s group reported the structure of stabilization of non-ionic and cationic surfactants on platinum nanoparticles [22] and that of ternary amines on rhodium nanoparticles [23]. Such information is considerably important for applications of nanoparticles such as... 

Park S, Xie Y, Weaver MJ. 2002. Electrocatal3dic pathways on carbon-supported platinum nanoparticles Comparison of particle-size-dependent rates of metbanol, formic acid, and formaldehyde electrooxidation. Langmuir 18 5792-5798. 

Andreaus B, Maillard F, Kocylo J, Savinova ER, Eikerling M. 2006. Kinetic modeling of COad monolayer oxidation on carbon-supported platinum nanoparticles. J Phys Chem B 110 21028-21040. 

Miki A, Ye S, Osawa M. 2002. Surface-enhanced IR absorption on platinum nanoparticles an apphcation to real-time moititoring of electrocatalytic reactions. Chem Commun (14) 1500-1501. 

Park S, Tong YY, Wieckowski A, Weaver MJ. 2002a. Infrared spectral comparison of electrochemical carhon monoxide adlayers formed by direct chemisorption and methanol dissociation on carbon-supported platinum nanoparticles. Langmuir 18 3233-3240. 

Rice C, Tong YY, Oldfield E, Wieckowski A, Hahn F, Gloaguen F, Leger J-M, Lamy C. 2000. In situ infrared study of carbon monoxide adsorbed onto commercial fuel-cell-grade carbon-supported platinum nanoparticles correlation with C NMR results. J Phys Chem B 104 5803-5807. 

Antoine O, Bultel Y, Durand R. 2001. Oxygen reduction reaction kinetics and mechanism on platinum nanoparticles inside Nafion . J Electroanal Chem 499 85-94. 

Gamez A, Richard D, Gallezot P, Gloaguen F, Faure R, Durand R. 1996. Oxygen reduction on well-defined platinum nanoparticles inside recast ionomer. Electrochim Acta 41 307-314. 

Genies L, Eaure R, Durand R. 1998. Electrochemical reduction of oxygen on platinum nanoparticles in alkaline media. Electrochim Acta 44 1317-1327. 

Gloaguen F, Leger JM, Lamy C. 1997. Electrocatal3ftic oxidation of methanol on platinum nanoparticles electrodeposited onto porous carhon substrates. J Appl Electrochem 27 ... 

Inaba M, Ando M, Hatanaka A, Nomoto A, Matsuzawa K, Tasaka A, Kinumoto T, Iriyama Y, Ogumi Z. 2006. Controlled growth and shape formation of platinum nanoparticles and their electrochemical properties. Electrochim Acta 52 1632-1638. 

Park S, Wasileski SA, Weaver MJ. 2001. Electrochemical infrared characterization of carbon-supported platinum nanoparticles A benchmark structural comparison with single-crystal electrodes and high-nuclearity carbonyl clusters. J Phys Chem B 105 9719 -9725. 

Solla-Gullon J, Vidal-Iglesias FJ, Rodriguez P, Herrero E, Feliu JM, Aldaz A. 2005. Shape-dependent electrocatalysis CO monolayer oxidation at platinum nanoparticles. Paper presented at Meeting ECS, May 15-20, 2005, Quebec City. 

Maye MM, Kariuiki NN, et al. 2004. Electrocatal3dic reduction of oxygen Gold and gold-platinum nanoparticle catalysts prepared by two-phase protocol. Gold Bull 37(3-4) 217-223. 

Wu C, Mosher BP, Zeng T (2006) Rapid synthesis of gold and platinum nanoparticles using metal displacement reduction with sonomechanical assistance. Chem Mater 18 2925-2928... 

Mizukoshi Y, Takagi E, Okuno H, Oshima R, Maeda Y, Nagata Y (2001) Preparation of platinum nanoparticles by sonochemical reduction of the Pt(IV) ions role of surfactants. Ultrason Sonochem 8 1-6... 

S. Hrapovic, Y. Liu, K.B. Male, and J.H.T. Luong, Electrochemical biosensing platforms using platinum nanoparticles and carbon nanotubes. Anal. Chem. 76, 1083-1088 (2004). 

CNTs offer an exciting possibility for developing ultrasensitive electrochemical biosensors because of their unique electrical properties and biocompatible nanostructures. Luong et al. have fabricated a glucose biosensor based on the immobilization of GOx on CNTs solubilized in 3-aminopropyltriethoxysilane (APTES). The as-prepared CNT-based biosensor using a carbon fiber has achieved a picoamperometric response current with the response time of less than 5 s and a detection limit of 5-10 pM [109], When Nation is used to solubilize CNTs and combine with platinum nanoparticles, it displays strong interactions with Pt nanoparticles to form a network that connects Pt nanoparticles to the electrode surface. The Pt-CNT nanohybrid-based glucose biosensor... 

H. Tang, J. Chen, S. Yao, L. Nie, G. Deng, and Y. Kuang, Amperometric glucose biosensor based on adsorption of glucose oxidase at platinum nanoparticle-modified carbon nanotube electrode. Anal. Biochem. 331, 89-97 (2004). 

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