Carbon nanocells and nanotubes grown in hydrothermal fluids

For the first time multiwall carbon nanocells (circle divide < 100 nm) and multiwall carbon nanotubes have been artificially grown in hydrothermal flu ids from amorphous carbon, at temperatures below 800<degrees>C, in the abse nce of metal catalysts. Carbon nanocells were the result of bubble growth o f graphitic multiwalls at 600 degreesC. Pristine multiwall nanotubes grow a t higher temperatures. At 800 degreesC, the condensed solids consist of def ect-free sp(2)-bonded multiwall nanocrystals. Hot hydrothermal fluids seem essential far the growth of curled patches of sp(2)-bouded carbon at low te mperatures. Hydrothermal synthesis of finite sp(2)-bonded nanotubes and car bon nanocrystals is possible in moderate conditions and easy to reproduce. (C) 2000 Elsevier Science B.V. All rights reserved.