Synthesis of single-walled carbon nanotubes using binary (Fe, Co, Ni) alloy nanoparticles prepared in situ by the reduction of oxide solid solutions

Passing a H-2-CH4 mixture over oxide spinels containing two transition elem ents as in Mg0.8MyMz'Al2O4 (M, M' = Fe, Co or Ni, y + z = 0.2) at 1070 degr ees C produces small alloy nanoparticles which enable the formation of carb on nanotubes. Surface area measurements are found to be useful for assessin g the yield and quality of the nanotubes. Good-quality single-walled nanotu bes (SWNTs) have been obtained in high yields with the FeCo alloy nanoparti cles, as evidenced by transmission electron microscope images and surface a rea measurements. The diameter of the SWNTs is in the 0.8-5 nm range, and t he multiwalled nanotubes, found occasionally, possess very few graphite lay ers. (C) 1999 Elsevier Science B.V. All rights reserved.