Carbon nanotubes filled with metallic nanowires

A facile method is proposed to use LaNi2 hydrogen storage alloy as a catalyst precursor to produce metallic nickel filled carbon nanotubes. Multi-walled carbon nanotubes filled with long continuous nickel nanowire with several microns in length are synthesized through chemical vapor deposition at low temperature (550degreesC). It is more efficient to fill Ni nanowires into nanotubes after the oxidation treatment of LaNi2 alloy at low temperatures, while the oxidation treatment at high temperature results in the forming of herringbone carbon nanofibers with tips of Ni nanoparticles. The metallic Ni nanowires inside the cores of carbon nanotubes could not be eliminated during the purification process in concentrated hydrochloric acid. The analysis of transmission electron microscopy (TEM), selected area electron diffraction (SAED) and X-ray diffraction (XRD) reveals that the metallic nickel nanowires filled inside carbon nanotubes exist as a single crystalline with fee structure. (C) 2003 Elsevier Ltd. All rights reserved.