Summary: We demonstrate in this communication that large‐scale coaxial nanocables of polypyrrole (PPy)/TiO2 can be obtained via three steps: (1) synthesis of TiO2 nanofibers by electrospinning; (2) physical adsorption Fe3+ oxidant on the surface of TiO2 nanofibers; (3) followed by polymerization of pyrrole (from vapor) on the surface of TiO2 nanofibers. During the synthesis, the PPy formed on TiO2 nanofibers as a template and formed PPy/TiO2 coaxial nanocables. TEM image proved that PPy (20 nm thickness) covered the surface of TiO2 nanofibers. Fourier‐transform infrared (FTIR), X‐ray photoelectron spectra (XPS), and X‐ray diffraction patterns (XRD) characterized the chemical structure of the coaxial nanocables. Surface photovoltage spectroscopy (SPS) revealed the surface properties of the PPy/TiO2 coaxial nanocables.
TEM image of individual PPy/TiO2 coaxial nanocable. 相似文献
Aligned coaxial nanocables were grown on Si substrates by a vapor-deposition technique. The lengths of the nanocables increased as the distance between the substrate and the source decreased. The nanocables were characterized as homogeneously crystallized shells of about 25 nm thick, diameters of about 100 nm, and round top ends. It was found that the shell emits an intense middle-ultraviolet about 300 nm at room temperature. This emission was attributed to the thin double-layer structure in the Zn-Zn2SiO4 core-shell nanocable where the Zn2SiO4 shell has the potential to serve as more ideal luminophors. The results demonstrated that the nanocable density could be changed by altering nucleation density at the steps on the substrate surface. The unique growth manner described herein provides a new technique for the homogeneous crystallization of Zn-Zn2SiO4 core-shell nanocables. 相似文献
One-dimensional gold/polyaniline (Au/PANI-CSA) coaxial nanocables with an average diameter of 50-60 nm and lengths of more than 1 mum were successfully synthesized by reacting aniline monomer with chlorauric acid (HAuCl(4)) through a self-assembly process in the presence of D-camphor-10-sulfonic acid (CSA), which acts as both a dopant and surfactant. It was found that the formation probability and the size of the Au/PANI-CSA nanocables depends on the molar ratio of aniline to HAuCl(4) and the concentration of CSA, respectively. A synergistic growth mechanism was proposed to interpret the formation of the Au/PANI-CSA nanocables. The directly measured conductivity of a single gold/polyaniline nanocable was found to be high (approximately 77.2 S cm(-1)). Hollow PANI-CSA nanotubes, with an average diameter of 50-60 nm, were also obtained successfully by dissolving the Au nanowire core of the Au/PANI-CSA nanocables. 相似文献
The morphology of CdSe/SiO(2) was manipulated from core-shell-structured nanoparticles to nanocables by using a chemical vapor deposition (CVD) process. The growth of nanocables, with cores no more than 20 nm in diameter, is initiated by the formation of core-shell nanoparticles with SiO(2) as matrix and CdSe clusters dispersed inside. After the subsequent vaporization of the SiO(2) matrix, the follow-up CdSe vapor crystallizes with the remaining CdSe clusters as nuclei to form CdSe nanowires as the furnace was cooled to 1200 degrees C. During the controlled cooling of the furnace, the SiO vapor re-deposits to sheathe the nanowires. The thickness of the shell and the diameter of core were successfully controlled. The photoluminescence measurements show that the CdSe/SiO(2) nanocables have strong visible-light emission bands located at 590 and 688 nm, which are attributed to the defects induced by SiO(2) sheaths nanowires and the quantum confinement effect of the CdSe, respectively. The UV/Vis absorption spectra of the naked CdSe nanowires further validate the above-mentioned quantum confinement effect. The deterministic growth of these nanocables is very important for the design of the nanodevices based on them. 相似文献
By using carbon nanotubes (CNTs) as a shape template and glucose as a carbon precursor and structure‐directing agent, CNT@Fe3O4@C porous core/sheath coaxial nanocables have been synthesized by a simple one‐pot hydrothermal process. Neither a surfactant/ligand nor a CNT pretreatment is needed in the synthetic process. A possible growth mechanism governing the formation of this nanostructure is discussed. When used as an anode material of lithium‐ion batteries, the CNT@Fe3O4@C nanocables show significantly enhanced cycling performance, high rate capability, and high Coulombic efficiency compared with pure Fe2O3 particles and Fe3O4/CNT composites. The CNT@Fe3O4@C nanocables deliver a reversible capacity of 1290 mA h g?1 after 80 cycles at a current density of 200 mA g?1, and maintain a reversible capacity of 690 mA h g?1 after 200 cycles at a current density of 2000 mA g?1. The improved lithium storage behavior can be attributed to the synergistic effect of the high electronic conductivity support and the inner CNT/outer carbon buffering matrix. 相似文献