Nitrogen controlled iron catalyst phase during carbon nanotube growth
- Author(s)
- Bernhard C. Bayer, Carsten Baehtz, Piran R. Kidambi, Robert S. Weatherup, Clemens Mangler, Jani Kotakoski, Caroline J. L. Goddard, Sabina Caneva, Andrea Cabrero-Vilatela, Jannik C. Meyer, Stephan Hofmann
- Abstract
Close control over the active catalyst phase and hence carbon nanotube structure remains challenging in catalytic chemical vapor deposition since multiple competing active catalyst phases typically co-exist under realistic synthesis conditions. Here, using in-situ X-ray diffractometry, we show that the phase of supported iron catalyst particles can be reliably controlled via the addition of NH3 during nanotube synthesis. Unlike polydisperse catalyst phase mixtures during H-2 diluted nanotube growth, nitrogen addition controllably leads to phase-pure gamma-Fe during pre-treatment and to phase-pure Fe3C during growth. We rationalize these findings in the context of ternary Fe-C-N phase diagram calculations and, thus, highlight the use of pre-treatment- and add-gases as a key parameter towards controlled carbon nanotube growth.
- Organisation(s)
- Physics of Nanostructured Materials
- External organisation(s)
- University of Cambridge, Helmholtz-Zentrum Dresden-Rossendorf
- Journal
- Applied Physics Letters
- Volume
- 105
- No. of pages
- 5
- ISSN
- 0003-6951
- DOI
- https://doi.org/10.1063/1.4897950
- Publication date
- 10-2014
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 210006 Nanotechnology, 103008 Experimental physics, 103009 Solid state physics
- Keywords
- ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/nitrogen-controlled-iron-catalyst-phase-during-carbon-nanotube-growth(8140e3eb-bd25-4772-9e36-8b21c33c9cb7).html