The role of catalyst support in carbon nanotube synthesis

Acetylene decomposition over supported cobalt (or iron) catalysts proved to be an effective method for the preparation of well-graphitized carbon nanotubes. Compared to other techniques, catalytic synthesis is operated under relatively mild reaction conditions (700 degrees C, atmospheric pressure) and experimental apparatus is very simple. In order to improve catalyst performance, we try to understand the reaction mechanism. Catalysts were prepared by the impregnation method using different materials as catalyst support. Physico-chemical characterization of the samples were carried out by XRD, IR, etc. Surface acidity was measured by pyridine adsorption technique.. Catalyst samples were tested in the decomposition of acetylene in a fixed bed flow reactor at 722 degrees C. The quantity of carbon deposit was weighted (catalyst activity). The quality of carbon nanotubes produced was characterized by means of transmission electron microscopy.