CUED Publications database

Nitrogen-induced catalyst restructuring for epitaxial growth of multiwalled carbon nanotubes.

Pattinson, SW and Ranganathan, V and Murakami, HK and Koziol, KKK and Windle, AH (2012) Nitrogen-induced catalyst restructuring for epitaxial growth of multiwalled carbon nanotubes. ACS Nano, 6. pp. 7723-7730.

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The ability to simply and economically produce carbon nanotubes (CNTs) with a defined chiral angle is crucial for the exploitation of nanotubes for their electrical properties. We investigate a diverse range of nitrogen sources for their ability to control CNT chiral angle via epitaxial growth from highly ordered catalyst particles. Through the use of in situ mass and infrared spectrometry, we elucidate the mechanism by which these ordered catalyst particles are formed, showing that ammonia is a key intermediate in the process. Subsequently, the direct addition of a small amount of ammonia to an otherwise standard CNT synthesis is shown to be able to form catalyst particles that grow single chiral angle multiwalled carbon nanotubes. Variation in the ammonia concentration clarifies the catalyst restructuring necessary for the epitaxial growth of carbon nanotubes and subsequent chiral angle control. The simple addition of a nitrogen source is an attractive route for chiral angle control; however, the model also suggests further ways to optimize CNT chiral angle distributions as well as to improve CNT and graphene yield and crystallinity. This understanding also explains the action of ammonia in its widely used role in activating catalyst prior to CNT growth. Finally, this work highlights the uses of novel surface geometries that are achievable through multiphase catalysts.

Item Type: Article
Uncontrolled Keywords: Catalysis Crystallization Macromolecular Substances Materials Testing Molecular Conformation Nanotubes, Carbon Nitrogen Particle Size Surface Properties
Depositing User: Cron Job
Date Deposited: 12 Sep 2018 20:18
Last Modified: 04 Jun 2020 14:46
DOI: 10.1021/nn301517g