Simple metal-catalyst-free production of carbon nanostructures

Abstract

We report the metal-catalyst-free production of multiwalled carbon nanotubes and nanobubbles, in a chemical reduction of hexachlorobenzene by metallic sodium, giving high yields (in excess of 80 %) and at temperatures as low as 190°C for multiwalled carbon nanotubes and 100°C for nanobubble formation. The carbon nanotube samples produced under solvothermal conditions were found to consist of large bundles of nanotubes (>50 µm) consistent with a facial growth from the surface of the molten metal. Meanwhile, the nanobubbles produced under ambient pressure were found to be small (≤1 µm), polydispersed (smallest ~50 nm), and the bulk to have a large microporous area. With the regulatory complexities and high environmental and economic costs of remediating waste containing highly hazardous halogenated aromatic chemicals, necessitating high-temperature incineration under strictly controlled conditions, this low-temperature, low-cost chemical degradation of hexachlorobenzene is of great potential as a scalable and workable remediation technology. © 2013, CSIRO Publishing.