Carbon Matrix (carbon + matrix)

Distribution by Scientific Domains


Selected Abstracts


LiFePO4 Nanoparticles Embedded in a Nanoporous Carbon Matrix: Superior Cathode Material for Electrochemical Energy-Storage Devices

ADVANCED MATERIALS, Issue 25-26 2009
Xing-Long Wu
An optimized nanostructure design for high-power, high-energy lithium-ion batteries and supercapacitors is realized by fabricating a nanocomposite with highly dispersed nanoparticles of active materials in a nanoporous carbon matrix. A nano-LiFePO4/nanoporous carbon matrix nanocomposite forms a bridge between a supercapacitor and a battery electrode and offers a reasonable compromise between rate and capacity. [source]


Nanogold-Loaded Sharp-Edged Carbon Bullets as Plant-Gene Carriers

ADVANCED FUNCTIONAL MATERIALS, Issue 15 2010
Periyasamy S. Vijayakumar
Abstract The higher DNA delivery efficiency into plants by gold nanoparticles embedded in sharp carbonaceous carriers is demonstrated. These nanogold-embedded carbon matrices are prepared by heat treatment of biogenic intracellular gold nanoparticles. The DNA-delivery efficiency is tested on a model plant, Nicotiana tabacum, and is further extended to the monocot, Oryza sativa, and a hard dicot tree species, Leucaena leucocephala. These materials reveal good dispersion of the transport material, producing a greater number of GUS foci per unit area. The added advantages of the composite carrier are the lower plasmid and gold requirements. Plant-cell damage with the carbon-supported particles is very minimal and can be gauged from the increased plant regeneration and transformation efficiency compared with that of the commercial micrometer-sized gold particles. This is ascribed to the sharp edges that the carbon supports possess, which lead to better piercing capabilities with minimum damage. [source]


LiFePO4 Nanoparticles Embedded in a Nanoporous Carbon Matrix: Superior Cathode Material for Electrochemical Energy-Storage Devices

ADVANCED MATERIALS, Issue 25-26 2009
Xing-Long Wu
An optimized nanostructure design for high-power, high-energy lithium-ion batteries and supercapacitors is realized by fabricating a nanocomposite with highly dispersed nanoparticles of active materials in a nanoporous carbon matrix. A nano-LiFePO4/nanoporous carbon matrix nanocomposite forms a bridge between a supercapacitor and a battery electrode and offers a reasonable compromise between rate and capacity. [source]


Fabrication and Characterization of Nanoporous Carbon/Silica Membranes,

ADVANCED MATERIALS, Issue 4 2005
B. Park
Nanoporous carbon/silica (C/SiO2) membranes (see Figure) with high permeabilities and high gas selectivities are prepared by the controlled pyrolysis of polyimide/silica (PI/SiO2) composites obtained from polymerization of alkoxysilanes in situ via a sol,gel reaction. The silica content and the nature of the silica network incorporated in the carbon matrix can be used to tune the gas permeation and separation properties of the final C/SiO2 membranes. [source]


Silver nanocluster containing diamond like carbon

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2008
F. Schwarz
Abstract Applying Diamond Like Carbon (DLC) as medical coating has become well established since large scale plasma processes like Plasma Immersion Ion Implantation and Deposition (PIII&D) are available. Now the focus of research lies on systematic modification of certain biological relevant properties and the most recent field of interest turned to generating antimicrobial behaviour. This is desirable for medical tools as well as for different types of medical implants. Since silver and copper are known to provide a bactericidal effect, one tries to introduce clusters of these noble metals into the carbon matrix. The basic principle of the method presented is to convert a metal containing polymer film into DLC by ion bombardment. In this paper the hydrogenated DLC matrix is characterized and the evolution of the metal particles is studied. By means of film composition (RBS/ERD), bonding structure (Raman spectroscopy) and hardness (nanoindentation), the dependency of these material properties on ion species, energy and fluence is investigated. TEM imaging is used to visualize the film structure. Upon ion irradiation of the polymer films, increased density and considerable loss of hydrogen can be observed, which both are controlled by ion fluence and mass. The crosslinking of the carbon network, caused by hydrogen drive out as well as atomic displacements in collision cascades, results in the formation of a-C:H. The silver particles in the film some ion induced growth, but still remain as nanoclusters in the a-C:H matrix. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Characterizations of nanostructured silicon-carbon films deposited on p-layer by PECVD

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010
U. Coscia
Abstract Nanostructured silicon carbon films composed of silicon nanocrystallites embedded in the amorphous silicon carbon matrix are prepared by a rf-PECVD system at 250 C from silane and methane gas mixture highly diluted in hydrogen onto 7059 Corning glass and p-layer deposited on tin oxide substrates by varying rf power from 25 to 65 W. The structural and compositional properties of the films have been investigated. The study demonstrates that rf power controls the crystalline fraction as well as the silicon crystallite size and that p-layer/tin oxide structure enhances the nucleation of silicon grains as compared to Corning glass ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Comparative Study of the Carbonisation of CoTMPP by Low Temperature Plasma and Heat Treatment

PLASMA PROCESSES AND POLYMERS, Issue 6 2010
Iris Herrmann
Abstract Low temperature plasma (LTP) treatment of cobalt-tetramethoxyphenylporphyrin (CoTMPP) has been applied as a promising alternative method to the conventional heat treatment in order to attain highly active catalysts for the electroreduction of oxygen. In this contribution it is shown that CoTMPP can be completely transformed into a carbon matrix by adjusting adequate LTP parameters. The carbonisation process of CoTMPP is investigated at different operation conditions by Raman and IR spectroscopy and compared with the structural features of the heat-treated samples. As a result it appears that the LTP occurs via a different carbonisation process, which yields in a more homogeneously defined molecular carbon structure. [source]


Impact of Annealing on the Conductivity of Amorphous Carbon Films Incorporating Copper and Gold Nanoparticles Deposited by Pulsed Dual Cathodic Arc

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
Jose Luis Endrino
Abstract The influence of annealing in argon at 300,C on the conductivity, phase stability and electronic structure of hydrogen-free amorphous carbon (a-C) films containing copper (a-C:Cu) and gold (a-C:Au) nanoclusters was investigated. The motivation of this work is twofold: (1) to study the thermal stability of a-C:Cu and a-C:Au films and (2) to point out the relevance of X-ray absorption near edge structure (XANES) technique to study the structural evolution of metal-doped a-C nanocomposites. The films were produced at room temperature using a selective-bias pulsed dual-cathode arc deposition technique. Compositional analysis was performed with secondary neutral mass spectroscopy whereas grazing incidence X-ray diffraction (GIXRD) was used to monitor phase transformation and identify the dispersion or agglomeration of the crystallites within the carbon matrix. XANES spectra at the C-K was used to investigate the effect of annealing in argon on the electronic structure of the a-C matrix, while Cu K and Au L-edges were investigated on a-C:Cu and a-C:Au samples, respectively, to study the nanocluster evolution. XANES showed that the a-C host matrix increased its graphitic character and that stress was relieved upon annealing. No relevant changes were observed in the Au arrangements in a-C:Au films. In the case of the a-C:Cu samples, the Cu-K XANES spectra indicated the formation of Cu2O crystals which correlated well with GIXRD spectra and the decrease in conductivity. [source]