Abstract
Thermal decomposition of a Ni‐containing organometallic compound or Ni salt in the presence of an excess amount of a multi(ethynyl)aromatic compound results in the formation of CNTs during the carbonization process. The uniqueness of the process is the formation of MWNTs in high yield within the solid carbonaceous domain upon heat treatment to elevated temperature under ambient pressure. The formation of MWNTs in a shaped, solid configuration readily occurred when the precursor mixture was heated above 600 °C. 1,2,4,5‐Tetrakis(phenylethynyl)benzene was reacted with varying amounts of a Ni‐containing compound in an organic solvent to produce the Ni adduct of the ethynyl unit. Other mixtures were formulated by physical mixing of 1,2,4,5‐tetrakis(phenylethynyl)benzene and a Ni salt. Heat treatment of the various mixtures to temperatures up to 1300 °C under atmospheric pressure resulted in the decomposition of the Ni‐containing compound or salt and the formation of Ni atoms, clusters, and/or nanoparticles in the polymeric‐to‐carbon nanoparticle‐to‐carbon nanotube compositions. The Ni atoms, clusters, and/or nanoparticles are the key to the formation of the carbon nanotubes. The resulting Ni nanoparticle–CNT compositions show magnetic properties. X‐ray diffraction, Raman spectroscopy, transmission electron microscopy, and scanning electron microscopy studies show the presence of a large quantity of MWNTs in the carbonaceous solid residue. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)