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Letter

In situ Observations of Catalyst Dynamics during Surface-Bound Carbon Nanotube Nucleation

Supporting Info

Stephan Hofmann,*^† Renu Sharma,^‡ Caterina Ducati,^§ Gaohui Du,^‡ Cecilia Mattevi,^# Cinzia Cepek,^# Mirco Cantoro,^† Simone Pisana,^† Atlus Parvez,^† Felipe Cervantes-Sodi,^† Andrea C. Ferrari,^† Rafal Dunin-Borkowski,^§ Silvano Lizzit, Luca Petaccia, Andrea Goldoni, and John Robertson^†

Department of Engineering, University of Cambridge, Cambridge CB3 0FA, UK, Center for Solid State Science, Arizona State University, Tempe, Arizona 85287-1704, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ, UK, Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark, University of Padova, Dipartimento di Scienze Chimiche, Via Marzolo no. 1, I-335131 Padova, Italy, Laboratorio Nazionale, TASC-CNR-INFM, s.s. 14, Km. 163.5, I-34012 Trieste, Italy, and Surface Science Division, Sincrotrone Trieste S.C.p.A., s.s. 14, Km. 163.5, I-34012 Trieste, Italy

Nano Lett., 2007, 7 (3), pp 602–608

DOI: 10.1021/nl0624824

Publication Date (Web): February 24, 2007

Abstract

We present atomic-scale, video-rate environmental transmission electron microscopy and in situ time-resolved X-ray photoelectron spectroscopy of surface-bound catalytic chemical vapor deposition of single-walled carbon nanotubes and nanofibers. We observe that transition metal catalyst nanoparticles on SiO_x support show crystalline lattice fringe contrast and high deformability before and during nanotube formation. A single-walled carbon nanotube nucleates by lift-off of a carbon cap. Cap stabilization and nanotube growth involve the dynamic reshaping of the catalyst nanocrystal itself. For a carbon nanofiber, the graphene layer stacking is determined by the successive elongation and contraction of the catalyst nanoparticle at its tip.

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