Synthesis of Carbon/Carbon Core/Shell Nanotubes with a High Specific Surface Area

Novel carbon/carbon core/shell nanotubes (C/C-NTs) composed of well-crystallized core carbon nanotubes (CNTs) and structurally disordered carbon shells were prepared for obtaining a new type of nanotube material with high specific surface area (SSA). The disordered carbon shells were prepared by coating polyaniline, (PANI) layers on the core CNTs through in situ polymerization and Subsequent carbonization. Chemical activation was conducted for the C/C-NTs with KOH at 1123 K to prepare activated C/C-NTs (AC/C-NTs). Scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction, Raman spectroscopy, and an adsorption analyzer were used to characterize the nanotube samples. The outer carbon shells thermally converted from the PANI layers are much less ordered and thus much more reactive than the CNTs. The AC/C-NTs tend to have Much higher SSA than that obtained by directly activating the CNTs, and the obtained SSA for the AC/C-NTs is as high as 2924 m(2)/g, which is the highest among the existing nanotube materials. TEM shows that the hollow structure and high crystallinity of the core CNTs were well preserved during carbonization and activation. The novel AC/C-NTs may find important applications in many areas such as supercapacitors, catalyst supports, adsorption, and hydrogen storage due to their superhigh SSA and nanotubular structure. The present work provides a way for preparing other core/shell nanotube or nanowire materials with high SSA.