In Situ TEM Observations on the Sulfur-Assisted Catalytic Growth of Single-Wall Carbon Nanotubes.
The effect of sulfur on the catalytic nucleation and growth of single-wall carbon nanotubes (SWCNTs) from an iron catalyst was investigated in situ by transmission electron microscopy (TEM). The catalyst precursor of ferrocene and growth promoter of sulfur were selectively loaded inside of the hollow core of multiwall CNTs with open ends, which served as a nanoreactor powered by applying a voltage inside of the chamber of a TEM. It was found that a SWCNT nucleated and grew perpendicularly from a region of the catalyst nanoparticle surface, instead of the normal tangential growth that occurs with no sulfur addition. Our in situ TEM observation combined with CVD growth studies suggests that sulfur functions to promote the nucleation and growth of SWCNTs by forming inhomogeneous local active sites and modifying the interface bonding between catalysts and precipitated graphitic layers, so that carbon caps can be lifted off from the catalyst particle.
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China.
Lili
L
Zhang
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China.
Peng-Xiang
PX
Hou
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China.
Shisheng
S
Li
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China.
Chao
C
Shi
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China.
Hong-Tao
HT
Cong
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China.
Chang
C
Liu
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China.
Hui-Ming
HM
Cheng
carbon nanotube synthesis; growth mechanism; growth promoter; in situ TEM study