Catalyst poisoning by amorphous carbon during carbon nanotube growth: fact or fiction?
The influence of amorphous carbon on FePt catalyst particles under chemical vapor deposition conditions typically applied for CNT growth is examined through two routes. In the first, FePt catalyst particles supported on alumina are exposed to a well-established cyclohexane thermal CVD reaction at various temperatures. At higher temperatures where self-pyrolysis leads to copious amorphous carbon and carbon tar formation, carbon nanotubes are still able to form. In the second route, an amorphous carbon film is first deposited over the catalyst particles prior to the CVD reaction. Even for reactions where further amorphous carbon is deposited due to self-pyrolysis, graphitization is still demonstrated. Our findings reveal that the presence of amorphous carbon does not prevent catalytic hydrocarbon decomposition and graphitization processes. We also show an additional catalytic reaction to be present, catalytic hydrogenation, a process in which carbon in contact with the catalyst surface reacts with H(2) to form CH(4).
IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany. christoph.schuenemann@iapp.de
Christoph
C
Schünemann
Franziska
F
Schäffel
Alicja
A
Bachmatiuk
Ute
U
Queitsch
Maria
M
Sparing
Bernd
B
Rellinghaus
Khalid
K
Lafdi
Ludwig
L
Schultz
Bernd
B
Büchner
Mark H
MH
Rümmeli