Composites with Metal Nanoparticles

The photochemical reduction has also been applied for synthesis of graphene-metal NPs. In this case, graphene-metal NPs nanocomposites were prepared by the irradiant white light instead of the chemical reducing agent In one report noble metal salts adsorbed on ultrasonication exfoliated graphene flakes, which were functionalized with ionic surfactants, were reduced 

Reprinted from reference [52]. Copyright 2012, with permission from Elsevier. 

BSA-RGO, and (f, g] PtNP-BSA-RGO. Reprinted with permission from reference [57]. Copyright 2010 American Chemical Society. 

Other methods Layer-by-layer (LBL) deposition and solid reaction are used to prepare graphene-MNPs sometimes. Zhu and Dong et al. reported a LBL self-assembly method for constructing a graphene/platinum NPs three-dimensional hybrids base on the 

They decorated GO sheets with aerosol Ag nanocrystals using an electrostatic force directed assembly technique at room temperature [60]. 

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Title Polymeric and Carbon Compositions with Metal Nanoparticles... 

In case of fuel cell cathodes, theoretical considerations were directed towards optimizing catalysts for O2 reduction [103]. This has led to the synthesis of Pt3Co/C nanocatalyst systems and preliminary results again indicate perfect agreement between the calculations and the wet electrochemical results obtained with metal nanoparticles of the composition which theory had recommended [106]. 

There are two more size effects playing the important role in properties of composite films with metal nanoparticles influence of the size of particle on its optical characteristics and on electron work function W. The increase of W with decreasing the particle size is due to the rise of potential of the positive charge remaining on nanoparticle after electron release. For spherical nanoparticle with radius R the dependence of W (eV) on R (A) according to work [5] looks like... 

Another example of this method is the synthesis of dual Au/Pt composites-the aqueous solutions of polyvinyl alcohol and poly-(JV>vinyl-2-pyrollidone) have been used [39] with polymerization in the solution after colloid particle formation. The aggregation of nanoparticles in this case does not usually take place however the polymerization conditions affect the homogeneity of the composite obtained. They show some catalytic propertks, characteristic of bimetallic catalysts. There were some reports on semiconductor composites with metal coatings such as CdS/Rh 40 A composites [44] and CdSe/Ag SO A composites [45]. The former system exhibits enhanced photochemical properties, the latter was used for investigation of Raman scattering of nanocomposites. 

To obtain composites of carbon with metal nanoparticles, organic gels can be impregnated with metal salt solutions before drying and pyrolysis processes... 

In addition, a variety of polymer composites with unique conductive and electric properties have been developed for skeletal muscle regeneration by combining polymers with metal nanoparticles (McKeon-Fischer and Freeman, 2011) and carbon nanombes (McKeon-Fischer et al., 2014). For example, McKeon-Fischer et al. (2011) has developed an electrospun scaffold through the combination of PCL with MWCNTs and a hydrogel consisting of polyvinyl alcohol and polyacrylic acid as a potential nanoactuator for skeletal muscle engineering. 

The composites of metal nanoparticles with polymer films have also been characterized by using SECM. Of particular interest is the composite of metal nanoparticles with conducting polymers as... 

PtRu nanoparticles can be prepared by w/o reverse micro-emulsions of water/Triton X-lOO/propanol-2/cyclo-hexane [105]. The bimetallic nanoparticles were characterized by XPS and other techniques. The XPS analysis revealed the presence of Pt and Ru metal as well as some oxide of ruthenium. Hills et al. [169] studied preparation of Pt/Ru bimetallic nanoparticles via a seeded reductive condensation of one metal precursor onto pre-supported nanoparticles of a second metal. XPS and other analytical data indicated that the preparation method provided fully alloyed bimetallic nanoparticles instead of core/shell structure. AgAu and AuCu bimetallic nanoparticles of various compositions with diameters ca. 3 nm, prepared in chloroform, exhibited characteristic XPS spectra of alloy structures [84]. 

The recent liquid phase synthetic techniques provide us the metal nanoparticles with the standard deviation smaller than 10%. So a lot of scientists have been attracted by an investigation on the transition from molecular to bulk properties from both the fundamental and technological points of view. Here we present our recent liquid phase techniques to control the size and composition of Au and FePt nanoparticles. 

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