Synthesis of single-wall carbon nanotubes and long nanotube ribbons with Ho/Ni as catalyst by arc discharge

The effect of a new bimetallic catalyst Ho/Ni for synthesis of single-walled carbon nanotubes (SWNTs) by arc discharge has been studied. Long ribbons consisting of roughly-aligned SWNT bundles were obtained by a modified arc discharge apparatus. Ribbon lengths can reach as much as 20 cm. Both elements Ho and Ni play important roles in the synthesis of SWNTs with high yield and purity. Changes in the Ho and Ni concentration in the catalyst hardly affect the diameter distribution of SWNTs, but the yield and purity of SWNTs are very sensitive to the concentration. An optimal range of Ho/Ni compositions for synthesis of SWNTs with relatively high purity and yield is given.