The STEM and TEM images of the carbon nanotubes were carried out using an aberration-corrected JEOL JEM-ARM200F Scanning Transmission Electron Microscope equipped with a cold emission source operated at 200kV. The morphologies of the carbon nanotubes were carried out using a Carl Zeiss Merlin high-resolution Field Emission Scanning Electron Microscope (FE-SEM). EDX imaging was acquired by an Oxford Ultim Max 100 EDS detector. A 5 nm Pt/Pd layer was deposited to increase SEM resolution.