Growing carbon nanotubes (CNTs) by arcing from graphite electrodes does not
demand a noble gas atmosphere: water will do! CO and HZ bubbles generated
by reaction of C vapor with water provide a quasi-inert atmosphere in which
multiwalled carbon nanotubes grow from the cathode. Using cobalt salt solu
tions instead of plain water, the authors obtained CNTs filled with metalli
c cobalt and elemental sulfur (see Figure), potentially useful as nanoprobe
s for magnetic force microscopy.