title: Importance of oxygen in the metal-free catalytic growth of single-walled carbon nanotubes from SiO(x) by a vapor-solid-solid mechanism.
abstract: To understand in-depth the nature of the catalyst and the growth mechanism of single-walled carbon nanotubes (SWCNTs) on a newly developed silica catalyst, we performed this combined experimental and theoretical study. In situ transmission electron microscopy (TEM) observations revealed that the active catalyst for the SWCNT growth is solid and amorphous SiO(x) nanoparticles (NPs), suggesting a vapor-solid-solid growth mechanism. From in situ TEM and chemical vapor deposition growth experiments, we found that oxygen plays a crucial role in SWCNT growth in addition to the well-known catalyst size effect. Density functional theory calculations showed that oxygen atoms can enhance the capture of -CH(x) and consequently facilitate the growth of SWCNTs on oxygen-containing SiO(x) NPs.
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China.
authors.forename: Bilu
authors.initials: B
authors.lastname: Liu
authors.forename: Dai-Ming
authors.initials: DM
authors.lastname: Tang
authors.forename: Chenghua
authors.initials: C
authors.lastname: Sun
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.forename: Wencai
authors.initials: W
authors.lastname: Ren
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Wan-Jing
authors.initials: WJ
authors.lastname: Yu
authors.forename: Li-Chang
authors.initials: LC
authors.lastname: Yin
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.forename: Chuanbin
authors.initials: C
authors.lastname: Jiang
authors.forename: Hui-Ming
authors.initials: HM
authors.lastname: Cheng
mesh_terms: D002384:Catalysis; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D011789:Quantum Theory; D012822:Silicon Dioxide / Q000737:chemistry*; D014835:Volatilization
chemical_list: D037742:Nanotubes, Carbon; D012822:Silicon Dioxide; D010100:Oxygen