Co-synthesis, purification and characterization of single- and multi-walled carbon nanotubes using the electric arc method

We report the simultaneous synthesis of single-walled (SWNT) and multi-walled (MWNT) carbon nanotubes using the electric arc method. Two distinct deposits are formed when an electric arc is struck between a Co/Ni impregnated carbon electrode (anode) and a graphite electrode (cathode). The cobweb-like deposit harvested from the walls of the growth chamber (chamber deposit) contained SWNT bundles while the MWNTs were present in the deposit formed at the tip of the cathode (cathode deposit). Energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and Raman spectroscopy of each deposit confirmed the presence of respective carbon nanotubes along with carbonaceous impurities. A systematic purification procedure for separating SWNT bundles from the rest of the impurities is discussed. The optimal yield of purified SWNT bundles is ∼25 wt.% of the as-prepared chamber deposit.