In-situ X-ray Photoelectron Spectroscopy Study of Catalyst−Support Interactions and Growth of Carbon Nanotube Forests

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• 作者：Cecilia Mattevi ; Christoph Tobias Wirth ; Stephan Hofmann ; Raoul Blume ; Mirco Cantoro ; Caterina Ducati ; Cinzia Cepek ; Axel Knop-Gericke ; Stuart Milne ; Carla Castellarin-Cudia ; Sheema Dolafi ; Andrea Gol
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：August 14, 2008
• 年：2008
• 卷：112
• 期：32
• 页码：12207-12213
• 全文大小：547K
• 年卷期：v.112,no.32(August 14, 2008)
• ISSN：1932-7455

文摘

We study catalyst support interactions during chemical vapor deposition of carbon nanotubes by in situ X-ray photoelectron spectroscopy over a wide range of pressures. We observe Fe 2+ and 3+ interface states for metallic Fe on Al₂O₃ in the absence of measurable Al reduction. This support interaction is much stronger than that on SiO₂, and it restricts Fe surface mobility. The resulting much narrower Fe catalyst particle size distribution on Al₂O₃ leads to a higher carbon nanotube nucleation density and a vertical nanotube alignment due to proximity effects. We record the growth kinetics of carbon nanotube forests by optical imaging to understand effects that contribute to growth termination.