Structural and chemical evolution of single-wall carbon nanotubes under atomic and molecular deuterium interaction

• Published in: Carbon (New York) Vol. 43; no. 5; pp. 1073 - 1083
• Main Authors: Lisowski, W., Keim, E.G., van den Berg, A.H.J., Smithers, M.A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2005; Elsevier Science
• Subjects: Carbon nanotubes; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Materials science; Microstructure; Physics; Scanning electron microscopy, Transmission electron microscopy, X-ray photoelectron spectroscopy; Specific materials; Carbon nanotubes; Microstructure; Scanning electron microscopy, Transmission electron microscopy, X-ray photoelectron spectroscopy; Deuterium; Molecular interaction; Singlewalled nanotube; Carbon
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2004.12.002

The interaction of atomic (D) and molecular (D 2) deuterium, as present in a (D + D 2) gas mixture, with single-wall carbon nanotubes (SWNTs) has been studied by means of a combination of scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The SWNT samples were exposed to the gas mixture, produced by thermal dissociation of D 2 on a hot W filament, its temperature, T W, being kept at 1020 and 1550 K for a deuterium pressure of 0.6 and 60 Pa, respectively. Prolonged interaction of the low-pressure (D + D 2) gas mixture produced at T W = 1020 K leads to a conglomeration of the SWNT bundles into larger diameter ropes of square and triangular cross-section, covered by nano-aggregates of graphite material. Both the coalescence of single SWNTs and a massive reconstruction of bundles of SWNTs into a “coral reef”-like structure were found to occur after prolonged exposure of SWNTs to the high-pressure (D + D 2) gas mixture produced at T W = 1550 K. This structure is formed by the encapsulated Fe nanoparticles and deuterocarbon-like species appearing as a result of the deuterium interaction with the SWNT bundles accompanied by partial erosion of the SWNT material. The XPS valence-band spectra disclose electronic features characteristic for a hydrogen-plasma modified multi-wall carbon nanotube (MWNT)-like structure as a result of an intensive (D + D 2) induced transformation of the SWNTs into the “coral reef”-like structure.