'Click' preparation of CuPt nanorod-anchored graphene oxide as a catalyst in water.
TL;DR: The results of this study clearly demonstrate that nonpolar CuPt nanorods immobilized on GO can function as a catalyst in an aqueous solution and that GO can be used as a catalytic nanorod support.
Abstract: In this paper, a simple and powerful method of producing nanoparticle-anchored graphene oxide (GO) composites using a 'click' reaction is demonstrated. This method affords a facile means of anchoring of nanoparticles with various shapes and sizes on the GO. CuPt nanorods with controlled size, aspect ratio (from 1 to 11), and uniformity are synthesized. Transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy measurements are made to monitor the formation and characterize the properties of the CuPt nanorod-grafted GO composites. Their catalytic properties in the water phase are investigated using an o-phenylenediamine oxidation reaction. The results of this study clearly demonstrate that nonpolar CuPt nanorods immobilized on GO can function as a catalyst in an aqueous solution and that GO can be used as a catalytic nanorod support.
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TL;DR: In this paper, a review article collectively introduces a variety of reactions for functionalization of CNTs and graphene and fabrication of their polymer nanocomposites and compares the significance of different functionalization approaches on their composite properties.
465 citations
TL;DR: The catalytic activity of metal nanoparticles (MNPs) is highly dependent on the nature of the support as mentioned in this paper, which includes a large surface area, strong metal-support interaction, and presence of active sites that participate in the reaction mechanism.
265 citations
TL;DR: A versatile platform for a highly efficient and stable graphene oxide (GO)-based optical sensor that exhibits distinctive ratiometric color responses and can be expanded easily to various other multifunctional, GO-based sensors by using alternate stimuli-responsive polymers.
Abstract: In this paper, we report the development of a versatile platform for a highly efficient and stable graphene oxide (GO)-based optical sensor that exhibits distinctive ratiometric color responses. To demonstrate the applicability of the platform, we fabricated a colorimetric, GO-based pH sensor that responds to a wide range of pH changes. Our sensing system is based on responsive polymer and quantum dot (QD) hybrids integrated on a single GO sheet (MQD-GO), with the GO providing an excellent signal-to-noise ratio and high dispersion stability in water. The photoluminescence emissions of the blue and orange color-emitting QDs (BQDs and OQDs) in MQD-GO can be controlled independently by different pH-responsive linkers of poly(acrylic acid) (PAA) (pKa = 4.5) and poly(2-vinylpyridine) (P2VP) (pKa = 3.0) that can tune the efficiencies of Forster resonance energy transfer from the BQDs to the GO and from the OQDs to the GO, respectively. As a result, the color of MQD-GO changes from orange to near-white to blue o...
157 citations
TL;DR: The fabrication of multifunctional nanostructure material is emerging as an important fi eld of research in connection with heterogeneous catalytic reaction and it is clear that the size effect of 3DOM structure with big pore size can remarkably improve the contact effi ciency between solid reactant and catalyst.
Abstract: The fabrication of multifunctional nanostructure material is emerging as an important fi eld of research in connection with heterogeneous catalytic reaction. [ 1 ] To design and synthesize high performance materials in terms of catalytic activity, understanding the properties affecting catalytic performance is of great importance. [ 2 ] The catalytic oxidation of diesel soot particles, emitted from diesel engines as a typical kind of solid particles, takes place on the three-phase boundary among a solid catalyst, a solid reactant (soot) and gaseous reactants (O 2 ). [ 3 ] So, the catalytic activity for soot oxidation is affected by two factors: the contact effi ciency between soot and catalyst, and the intrinsic activity of material. [ 4 ] Three-dimensionally ordered macroporous (3DOM) materials have become a focus research topic due to their potential applications, such as catalysts, photonic crystals and energetic materials. [ 5 ] It is clear to realize that the size effect of 3DOM structure with big pore size ( > 50 nm) can remarkably improve the contact effi ciency between solid reactant and catalyst. [ 6 ] And the coordinatively unsaturated cation sites in noble-metal/oxide catalysts are essential for their good intrinsic catalytic properties. [ 7 ] For effi ciently catalyzing a deep oxidation reaction, the design of multifunctional nanocatalyst with the high density of active sites on the surface of 3DOM oxides is generally required and it still needs an intensive study. Ce-based oxide-supported Pt nanoparticle catalysts are critical to many important commercial chemical processes with utmost practical importance. [ 8 ] The catalytic performances of model systems with Pt nanoparticles dispersed on a porous or fl at substrate oxide supports often show strong structure and size dependencies duo to so-called “the strong metal–support interactions” (SMSI) occurring at the interface between the active (Pt) phase and the support. [ 9 ] In
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26,456 citations
TL;DR: The direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers is reported, and two different methods of patterning the films and transferring them to arbitrary substrates are presented, implying that the quality of graphene grown by chemical vapours is as high as mechanically cleaved graphene.
Abstract: Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.
10,033 citations
TL;DR: It is reported that chemically converted graphene sheets obtained from graphite can readily form stable aqueous colloids through electrostatic stabilization, making it possible to process graphene materials using low-cost solution processing techniques, opening up enormous opportunities to use this unique carbon nanostructure for many technological applications.
Abstract: Graphene sheets offer extraordinary electronic, thermal and mechanical properties and are expected to find a variety of applications. A prerequisite for exploiting most proposed applications for graphene is the availability of processable graphene sheets in large quantities. The direct dispersion of hydrophobic graphite or graphene sheets in water without the assistance of dispersing agents has generally been considered to be an insurmountable challenge. Here we report that chemically converted graphene sheets obtained from graphite can readily form stable aqueous colloids through electrostatic stabilization. This discovery has enabled us to develop a facile approach to large-scale production of aqueous graphene dispersions without the need for polymeric or surfactant stabilizers. Our findings make it possible to process graphene materials using low-cost solution processing techniques, opening up enormous opportunities to use this unique carbon nanostructure for many technological applications.
8,534 citations
IBM1
TL;DR: Thermal annealing converts the internal particle structure from a chemically disordered face- centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies that can support high-density magnetization reversal transitions.
Abstract: Synthesis of monodisperse iron-platinum (FePt) nanoparticles by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine stabilizers is reported. The FePt particle composition is readily controlled, and the size is tunable from 3- to 10-nanometer diameter with a standard deviation of less than 5%. These nanoparticles self-assemble into three-dimensional superlattices. Thermal annealing converts the internal particle structure from a chemically disordered face-centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies. These assemblies are chemically and mechanically robust and can support high-density magnetization reversal transitions.
5,568 citations
TL;DR: It is demonstrated that semiconductor nanorods can be used to fabricate readily processed and efficient hybrid solar cells together with polymers and Tuning the band gap by altering the nanorod radius enabled us to optimize the overlap between the absorption spectrum of the cell and the solar emission spectrum.
Abstract: We demonstrate that semiconductor nanorods can be used to fabricate readily processed and efficient hybrid solar cells together with polymers. By controlling nanorod length, we can change the distance on which electrons are transported directly through the thin film device. Tuning the band gap by altering the nanorod radius enabled us to optimize the overlap between the absorption spectrum of the cell and the solar emission spectrum. A photovoltaic device consisting of 7-nanometer by 60-nanometer CdSe nanorods and the conjugated polymer poly-3(hexylthiophene) was assembled from solution with an external quantum efficiency of over 54% and a monochromatic power conversion efficiency of 6.9% under 0.1 milliwatt per square centimeter illumination at 515 nanometers. Under Air Mass (A.M.) 1.5 Global solar conditions, we obtained a power conversion efficiency of 1.7%.
4,898 citations