Fe Nanoparticles (fe + nanoparticle)

Distribution by Scientific Domains


Selected Abstracts


Large-Scale Synthesis, Annealing, Purification, and Magnetic Properties of Crystalline Helical Carbon Nanotubes with Symmetrical Structures,

ADVANCED FUNCTIONAL MATERIALS, Issue 9 2007
J. Tang
Abstract Crystalline helical carbon nanotubes (HCNTs) are synthesized as the main products in the pyrolysis of acetylene at 450,C over Fe nanoparticles generated by means of a combined sol,gel/reduction method. Transmission electron microscopy (TEM) images reveal that there are two HCNTs attached to each Fe3C nanoparticle, and that the two HCNTs are mirror images of each other. Annealing in Ar at 750,C and purification by immersion in hot (90,C) HCl solution do not significantly change the structure of the HCNTs, despite the partial removal of Fe nanoparticles by the latter treatment. The magnetic properties of the as-prepared, annealed, and purified HCNTs have been systematically examined. The annealed sample shows relatively high magnetization due to the ferromagnetic ,-Fe nanoparticles encapsulated in the HCNT nodes. In the case of HCl treatment, relatively pure HCNTs are obtained by the removal of ferromagnetic nanoparticles from the double-HCNT nodes. The effects of the amount of catalyst used in the synthesis process on the morphology and yield of the carbon products have also been investigated. [source]


Polymer Nanocomposites Using Urchin-Shaped Carbon Nanotube-Silica Hybrids as Reinforcing Fillers

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 21 2004
Wei-De Zhang
Abstract Summary: Carbon nanotubes (CNTs) have been grown on MCM-41 supported Fe nanoparticles and the as-prepared (no further purification) CNT-silica hybrid was directly incorporated into nylon-6 (PA6) by simple melt-compounding. The urchin-shaped CNT-silica hybrid filler was observed to be homogeneously dispersed throughout the matrix by scanning electron and transmission electron microscopy. Compared with neat PA6, the tensile modulus and strength of the composite are greatly improved by about 110%, with incorporation of only 1 wt.-% CNT-silica filler. SEM image and schematic representation showing polymer chains wrapping around the urchin-shaped CNT-silica hybrid filler. [source]


Shape-controlled synthesis of Fe nanoparticles with high- Ms via modest-temperature reduction method

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 12 2007
H. T. Yang
Abstract To minimize the oxidation of Fe nanoparticles, 3 to 12 nm Fe nanoparticles have been synthesized by the modest-temperature reduction of FeCl2 in a non-polar solvent. Trioctylphosphine oxide and oleylamine were used to avoid additional oxidation introduced by surfactants in comparison with oleic acid. The magnetic properties of Fe nanoparticles with different sizes reveal that the saturation magnetization (Ms) of larger than 8.0 nm Fe nanoparticles is over 180 emu/g at 300 K. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Proximity magnetoresistance in Ag70Fe30 and Ag74Fe26 cosputtered granular films

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004
P. Allia
Abstract Granular films of composition Ag70Fe30 and Ag74Fe26 were prepared by dc plasma sputtering deposition in Ar atmosphere on Si substrates. Magnetization and magnetoresistance were measured between 2 K and 270 K. Both films exhibit a negative magnetoresistance (MR). The MR vs. reduced magnetisation curves are characterised by a box-like behavior, as already observed in magnetic systems with competing interactions. A standard analysis indicates that in both systems individual Fe nanoparticles are magnetically correlated over large distances. ( 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Enhanced dechlorination of trichloroethylene by membrane-supported Pd-coated iron nanoparticles

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2008
Linfeng Wu
Abstract In this study, cellulose acetate (CA) supported iron and Pd/Fe nanoparticles were used for dechlorination of trichloroethylene (TCE) from water. Solution and microemulsion methods were used to synthesize the iron nanoparticles. Pd/Fe bimetallic particles were prepared by postcoating Pd on the prepared iron nanoparticles. These materials were then dispersed in CA solution, which was used to prepare the membrane-supported nanoparticles. TEM imaging confirmed that the iron and Pd/Fe bimetallic nanoparticles were ,10 nm in diameter. The results of dechlorination studies showed that the surface composition of the Pd/Fe bimetallic nanoparticles (microemulsion method) significantly affected the observed reduction rate constant. In addition, the rate constant was a nonlinear function of metal loading and initial TCE concentration. A comparative study for the Pd/Fe (Pd 1.9 wt %) nanoparticles from solution and microemulsion methods showed that the nanoparticles formed by the latter method gave superior performance for the dechlorination of TCE. 2008 American Institute of Chemical Engineers Environ Prog, 2008 [source]