Nanowire

About: Nanowire is a research topic. Over the lifetime, 52095 publications have been published within this topic receiving 1532276 citations. The topic is also known as: nanowire.

Ferromagnetic CoPt3 Nanowires: Structural Evolution from fcc to Ordered L12

Abstract: This investigation demonstrates the magnetic properties and nanostructures of CoPt3 wire arrays that were fabricated by electrodeposition using a porous alumina template. The X-ray absorption analysis clearly verified the occurrence of a phase transition in CoPt3 nanowires. This phase transition significantly influences the magnetic properties and enhances coercivity and squareness. The phase transition of CoPt3 nanowires was from a random alloy distribution to anisotropically ordered CoPt3 (L12). The thermally induced phase transition of CoPt3 nanowires to ordered L12 CoPt3 through a “cluster-in-cluster” intermediate state via interdiffusion processes is revealed. The mechanism exhibited by these CoPt3 nanowires is proposed to explain the strong correlation between their magnetic character and their atomic distribution.

High catalytic activities of palladium nanowires synthesized using liquid crystal templating approach

Abstract: Synthesis of palladium (Pd) nanoparticles of various morphologies using swollen liquid crystalline (SLC) phases as structure directing templates is described in the present paper. The Pd precursor, bisdibenzyledene acetone palladium (Pd(DBA) 2 ) was dissolved in the oil phase of a hexagonal lyotropic liquid crystalline phase. The characteristic nature of the hexagonal mesophase was confirmed using polarized optical microscopy. The hexagonal mesophases were exposed to hydrogen gas for the synthesis of Pd nanoparticles. The nanomaterials were characterized using UV–vis spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). These nanowires showed very good catalytic activity for reduction of 4- nitrophenol to 4-aminophenol when compared to the spherical Pd nanoparticles. A comparative study revealed that the catalytic activity of the nanowires was much better than even very small Pd nanoparticles that are reported in the literature. The nanowires also had a very good catalytic activity in Suzuki-Miyaura coupling reactions for the synthesis of biphenyl even using aryl chlorides as reactant.

The Mechanism of Ni-Assisted GaN Nanowire Growth.

Abstract: Despite the numerous reports on the metal-catalyzed growth of GaN nanowires, the mechanism of growth is not well understood. Our study of the nickel-assisted growth of GaN nanowires using metalorganic chemical vapor deposition provides key insights into this process. From a comprehensive study of over 130 nanowires, we observe that as a function of thickness, the length of the nanowires initially increases and then decreases. We attribute this to an interplay between the Gibbs–Thomson effect dominant in very thin nanowires and a diffusion induced growth mode at larger thickness. We also investigate the alloy composition of the Ni–Ga catalyst particle for over 60 nanowires using energy dispersive X-ray spectroscopy, which along with data from electron energy loss spectroscopy and high resolution transmission electron microscopy suggests the composition to be Ni2Ga3. At the nanowire growth temperature, this alloy cannot be a liquid, even taking into account melting point depression in nanoparticles. We henc...