Catalyst Poisoning by Amorphous Carbon during Carbon Nanotube Growth: Fact or Fiction?

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• 作者：Christoph Schünemann ; Franziska Schäffel ; Alicja Bachmatiuk ; Ute Queitsch ; Maria Sparing ; Bernd Rellinghaus ; Khalid Lafdi ; Ludwig Schultz ; Bernd Büchner ; Mark H. Rümmeli
• 刊名：ACS Nano
• 出版年：2011
• 出版时间：November 22, 2011
• 年：2011
• 卷：5
• 期：11
• 页码：8928-8934
• 全文大小：1015K
• 年卷期：0
• ISSN：1936-086X

文摘

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 H₂ to form CH₄.