BERLIN, Feb. 6 (UPI) -- German scientists have used igneous rock from Mount Etna to produce carbon nanotubes and fibers.
Carbon nanotubes and fibers -- tiny structures made of pure carbon -- have become indispensable in nanoscience. However, because their production on an industrial scale remains expensive, their commercial use has remained elusive.
Now Dang Sheng Su and colleagues at the Fritz Haber Institute in Berlin have found naturally occurring iron oxide particles in lava make it an effective natural catalyst, possibly leading to a more efficient production method.
Etna, the most active European volcano, emitted several million cubic meters of lava during 2002 and 2003. Su and his colleagues found the mineral-rich lava rock can be amazingly helpful in the synthesis of carbon nanotubes and fibers.
The researchers pulverize the rocks and heat them to 700 degrees Celsius in a hydrogen atmosphere. That reduces the rocks' iron oxide particles to elemental iron.
When a mixture of hydrogen and ethylene is directed over the powder, the iron particles catalyze the decomposition of ethylene to elemental carbon. That is deposited on the lava rock in the form of nanotubes and fibers.
The study appears in the journal Angewandte Chemie.