Synthesis of carbon nanotubes by defluorination of PTFE with silicon

Nowadays, there is a strong interest in carbon nanotubes (CNTs) since these nanostructured materials have large potential applications in different technological fields. In this work, a very simple approach for synthesizing CNTs in mild conditions has been developed and investigated. In particular, the nanotubes have been obtained by thermal defluorination of poly(tetrafluoroethylene) (PTFE) by Si, which also acts as an inorganic catalyst for the CNT growth. Fine powders of PTFE and Si were homogeneously mixed together and then compacted by cold pressing. The obtained composite pills were placed into a quartz tube furnace at 650 degrees C, and a vacuum was applied to remove the gaseous by-product (SiF4). The obtained pyrolysis product consisted of CNTs, wrapping the surface of silicon grains. CNTs have been characterized by scanning electron microscopy, Raman spectroscopy, and large angle x-ray powder diffraction.