Double-wall carbon nanotubes synthesized by the abnormal glow discharge plasma method

摘要

Double-wall carbon nanotubes (DWCNTs) and single-wall carbon nanotubes (SWCNTs) have been synthesized by the DC abnormal glow discharge plasma CVD method using methane and hydrogen gas on a Si substrate coated with catalyst.Fe(NO_3)_2 and Mo(CH_3COCHCOCH_3)_2O_2 with Al_2O_3 supportwere used as catalysts.The growth temperatures were 1000-1400 degC and the gas pressures were 9kPa-13kPa.DC plasma was generated between an array of four W cathodes and a Cu disk anode,and the applied power was 4000-10000 W (2.5-4.0 A per cathode,400-800 V).Samples were characterized by high-resolution transmission electron microscopy (HRTEM) and micro-Raman spectroscopy using 514.5 nm Ar ion laser excitation.The HRTEM images showed that many carbon nanotubes had a concentric cylindrical graphene layer structure (DWCNTs).We measured the diameters of the carbon nanotubes (CNTs) from HRTEM images.The outer diameter of the DWNT was 1.52-1.64 nm and the inner diameter of the DWNT was 0.73-0.81nm.