Nanoparticle-assisted microwave absorption by single-wall carbon nanotubes

We report the effects of microwave irradiation on both unpurified and purified iron-catalyzed high-pressure disproportionation (HiPco)-grown single-walled carbon nanotubes (SWNTs) in ultrahigh vacuum. Under microwave irradiation, we observe that unpurified HiPco SWNTs quickly reach temperatures of approximately 1850 degreesC. As a result, H-2, H2O, CO, CO2, and CH4 gases are observed, and the Fe catalyst nanoparticles melt and coalesce into larger crystallites approximately four times their original diameter. In contrast, carbon black and purified HiPco SWNTs heat up to temperatures of 500-650 degreesC. We propose that the significant heating of unpurified HiPco SWNTs is due to the Fe catalysts. (C) 2003 American Institute of Physics.