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Synthesis of High‐Quality, Double‐Walled Carbon Nanotubes in a Fluidized Bed Reactor
Author(s) -
Liu Y.,
Qian W. Z.,
Zhang Q.,
Ning G. Q.,
Luo G. H.,
Wang Y.,
Wang D. Z.,
Wei F.
Publication year - 2009
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.200800298
Subject(s) - fluidized bed , carbon nanotube , catalysis , space velocity , materials science , chemical engineering , sintering , nucleation , cracking , carbon fibers , packed bed , batch reactor , metallurgy , chemistry , composite material , organic chemistry , selectivity , composite number , engineering
Double‐walled carbon nanotubes (DWCNTs) were synthesized in a packed bed reactor (PBR) and a fluidized bed reactor (FBR) by cracking CH 4 on a Fe/MgO catalyst. It is observed that the dominant carbon product changes drastically from DWCNTs to multi‐walled CNTs along the axial direction of PBR. The studies indicated that the high concentration of H 2 from the high conversion of CH 4 causes the quick reduction and sintering of the iron catalyst and inhibits the nucleation of DWCNTs. Based on these results, the batch or continuous feeding mode of small amounts of catalyst was adopted in a FBR to maintain a high space velocity of CH 4 and to inhibit the negative effect of excess H 2 . Finally, a DWCNT product with a specific surface area of 950 m 2 /g and a purity of 98 %, was obtained.