A simple and universal method for fabricating linear carbon chains in multiwalled carbon nanotubes

Long linear carbon chains (C-chains) have been fabricated inside multiwalled carbon nanotubes (MWCNTs) by a simple method based on high-temperature treatment of MWCNTs with the innermost tube diameters of ~0.7nm. The MWCNTs were prepared by hydrogen arc discharge, and then were fully purified by heat-treatment in air. After the purified MWCNTs were heated at 1500°C in inert atmosphere, the characteristic Raman peak of carbon nanowires (CNWs) were found to appear at ~1855cm−1, showing the formation of C-chain inside MWCNTs, i.e. C-chain@MWCNT. Raman spectra of CNWs prepared by high-temperature treatment of MWCNTs including double-walled carbon nanotubes and by hydrogen arc discharge are compared, and the formation mechanism is discussed. ► A simple method for fabricating carbon chains by high-temperature treatment of MWCNTs. ► A universal method for controllable growth of carbon nanowires. ► The growth mechanism of carbon nanowires.