Mechanisms of titania nanoparticle mediated growth of turbostratic carbon nanotubes and nanofibers
Journal of Applied Physics
American Institute of Physics
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Kudo, A., Steiner, S., Bayer, B., Kidambi, P., Hofmann, S., Strano, M., & Wardle, B. (2017). Mechanisms of titania nanoparticle mediated growth of turbostratic carbon nanotubes and nanofibers. Journal of Applied Physics, 122 (1. 014301)https://doi.org/10.1063/1.4990291
Turbostratic carbon nanotubes (CNTs) and nanofibers (CNFs) are synthesized by chemical vapor deposition using titania nanoparticle catalysts, and a quantitative lift-off model is developed to explain CNT and CNF growth. Micron-scale long turbostratic CNTs and CNFs were observed when acetylene is utilized as a carbon feedstock, and an alumina substrate was incorporated to improve the homogeneity of catalyst distribution. Turbostratic CNTs/CNFs are always found attached to nanoparticle corners, in the absence of the graphitic cage that is typically observed with metal nanoparticle-mediated growth. The observed morphology in turbostratic CNTs/CNFs supports a model in which several layers of graphene lift off from high-curvature corners of the titania nanoparticle catalysts. This model explains a key feature, which differentiates the growth of turbostratic CNTs/CNFs via non-metallic nanoparticles from growth using standard metal nanoparticle catalysts. The observed CNT/CNF growth and the accompanying model can impact the assessment of other metal-oxide nanoparticle catalysts, with the findings here contributing to a metal-free synthesis of turbostratic CNTs/CNFs.
This material is based upon work supported by the National Science Foundation under Grant No. 1007793 and was also supported by Airbus, Boeing, Embraer, Lockheed Martin, Saab AB, Spirit AeroSystems Inc., Textron Systems, ANSYS, Hexcel, and TohoTenax through MIT’s NanoEngineered Composite aerospace STructures (NECST) Consortium. This research was supported (in part) by the U.S. Army Research Office under Contract No. W911NF- 13-D-0001. This work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under NSF Award No. ECS-0335765. CNS is part of Harvard University. This work was carried out in part through the use of MIT Microsystems Technology Laboratories. Stephan Hofmann acknowledges funding from EPSRC under Grant No. EP/H047565/1.
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External DOI: https://doi.org/10.1063/1.4990291
This record's URL: https://www.repository.cam.ac.uk/handle/1810/266945