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Metal-semiconductor hybrid heteronanostructures may exhibit not only a combination of properties from the disparate components but also further enhanced property tunability and new synergistic properties that arise from the interactions between the metal and semiconductor components. Here we demonstrate that the Au–Cu2O hybrid core–shell nanoparticles not only combine the optical signatures of Cu2O nanoshells and the plasmonic properties of Au nanoparticles but exhibit further enhanced and expanded plasmonic tunability as well due to the dielectric properties of the Cu2O shells surrounding the Au cores. We have developed a robust wet chemistry approach through which we can fine-control several important geometrical parameters of the Au–Cu2O core–shell nanoparticles, such as Cu2O shell thickness, size of the Au core, and the spacing between the core and shell, to systematically and selectively fine-tune the synergistic light absorption and scattering properties of the particles over a broad spectral range across the visible and near-infrared regions. We have further performed Mie scattering theory calculations to theoretically interpret the correlation between the geometrical parameters and optical characteristics of the Au–Cu2O hybrid nanoparticles. Such optical tunability achieved through the fine-control over core and shell geometries is believed to be important to the optimization of the overall performance of hybrid heteronanostructure-based materials and/or devices for photonic, electronic, and optoelectronic applications. [ABSTRACT FROM AUTHOR]

Conducting polymer-macroporous carbon composite electrode materials were prepared by deposition of a thin layer of polyaniline (PANI) on the surface of three-dimensionally ordered macroporous carbon. A specific capacitance of 1490 F/g was observed over the deposited PANI in the composite electrode. Good rate performance and cycle ability were realized on the composite electrode, attributed to the combined contribution from both the unique properties of the carbon matrix (e.g., highly ordered interconnected pores and good electrical conductivity) and pseudocapacitance of the deposited PANI layer. The three-dimensionally ordered pore structure of the carbon favored the diffusion of the electrolyte ions, hence not only improving the energy storage capacity but also enhancing power density. [ABSTRACT FROM AUTHOR]

We report a one-step solvothermal method to prepare magnetic hybrid copolymer–Co hierarchical hollow spheres by localized Ostwald ripening. The initial stage is the aggregation of primary inorganic nanoparticles whose surfaces are partially adsorbed by copolymer PEG–PPG–PEG to form solid spheres followed by hollowing of the core and the progressive matter redistribution from the interior to the exterior. Meanwhile, amorphous inorganic particles grow to cubic crystallites. Finally, a hollow spherical architecture with an extensively roughened surface is obtained by this self-transformation. The effect of NaOH concentration (served as a catalyst and reagent) on the sphere morphology is also checked by time-dependent experiments. When decreasing the mass of NaOH from 7.5 to 2.5 mmol, a morphology transformation from porous hollow spheres to double-wall spheres and then to single-wall spheres with platelet-like building units aligned disorderly on the outer surfaces is observed, and this morphology transformation is related to Ostwald ripening. Our results suggest that these nanoparticle-based hollow hierarchical spheres collected by the self-transformation of precursor objects could be of potential applicability in the fields of material science and biomedical technology. [ABSTRACT FROM AUTHOR]

CuNi dendritic material has been obtained by the electrochemical method. For the synthesis of the material, different potentials were applied to get the dendritic structure in the aqueous solution. The materials were characterized by a series of techniques. The morphology of the material was characterized by field-emission scanning electron microscopy and high-resolution transmission electron microscopy. Energy-dispersive spectroscopy was applied to analyze the elemental composition. X-ray diffraction was used to check the crystal structure of the deposit. The dendritic morphology formation mechanism is discussed from the aspects of thermodynamics and kinetics to give a deep understanding of the crystal growth. For the potential practical application of the material in the fuel cell and biosensor, the electro-oxidation ability of glucose in alkaline solution was tested, and the sensor based on this dendritic alloy was tried. [ABSTRACT FROM AUTHOR]

This study reports an approach for synthesis of graphitic carbon nanocages (CNCs) via pyrolysis of ethanol with dissolved iron carbonyl at temperatures from 600 to 900 °C. The in situ formed Fe catalyst and template enabled the in situ generation of carbon from ethanol and formation of graphitic layers on the template surface. With the removal of the template, hollow CNCs were obtained to have a fine size of 30−50 nm and a large surface area of 400−800 m2/g. The CNCs also became dispersible in water without aggregation and settling after several months through HNO3treatment. As an example for potential applications, the CNCs were demonstrated to be a good material for supporting the Pt catalyst used in low-temperature fuel cells. Considering its continuous and low-temperature operation, in situ formation of catalyst and template, and in situ graphitization of decomposed carbon, the present approach may be suitable for large-scale production of high surface area and water-dispersible graphitic carbon and would be practically relevant for many technologies. [ABSTRACT FROM AUTHOR]