title: The Application of Gas Dwell Time Control for Rapid Single Wall Carbon Nanotube Forest Synthesis to Acetylene Feedstock.
abstract: One aspect of carbon nanotube (CNT) synthesis that remains an obstacle to realize industrial mass production is the growth efficiency. Many approaches have been reported to improve the efficiency, either by lengthening the catalyst lifetime or by increasing the growth rate. We investigated the applicability of dwell time and carbon flux control to optimize yield, growth rate, and catalyst lifetime of water-assisted chemical vapor deposition of single-walled carbon nanotube (SWCNT) forests using acetylene as a carbon feedstock. Our results show that although acetylene is a precursor to CNT synthesis and possesses a high reactivity, the SWCNT forest growth efficiency is highly sensitive to dwell time and carbon flux similar to ethylene. Through a systematic study spanning a wide range of dwell time and carbon flux levels, the relationship of the height, growth rate, and catalyst lifetime is found. Further, for the optimum conditions for 10 min growth, SWCNT forests with ~2500 μm height, ~350 μm/min initial growth rates and extended lifetimes could be achieved by increasing the dwell time to ~5 s, demonstrating the generality of dwell time control to highly reactive gases.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. matsumoto-naoyuki@aist.go.jp.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Matsumoto
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. oshima-azusa@aist.go.jp.
authors.forename: Azusa
authors.initials: A
authors.lastname: Oshima
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. shunsuke-sakurai@aist.go.jp.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Sakurai
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. takeo-yamada@aist.go.jp.
authors.forename: Takeo
authors.initials: T
authors.lastname: Yamada
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. m.yumura@aist.go.jp.
authors.forename: Motoo
authors.initials: M
authors.lastname: Yumura
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. kenji-hata@aist.go.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Hata
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. d-futaba@aist.go.jp.
authors.forename: Don N
authors.initials: DN
authors.lastname: Futaba
keywords: acetylene; carbon flux; dwell time; single-walled carbon nanotubes; water-assisted chemical vapor deposition