Nanocatalyst shape and composition during nucleation of single-walled carbon nanotubes
Jose Gomez-Ballesteros, Juan Burgos, Pin A. Lin, Renu Sharma, Perla Balbuena
The dynamic evolution of nanocatalyst particle shape and carbon composition is examined through the initial stages of the single walled-carbon nanotubes chemical vapor deposition synthesis via classical reactive and ab initio molecular dynamics simulations along with environmental tunneling electron microscope video imaging analyses. A clear migration of carbon is detected from the nanocatalyst/substrate interface, leading to a C-gradient showing C enrichment of the nanocatalyst layers in the immediate vicinity of the contact layer. However, as the metal nanocatalyst particle becomes saturated with carbon, a dynamic equilibrium is established with carbon precipitating on the surface and nucleating a carbon cap that is the precursor of nanotube growth. A carbon composition profile decreasing towards the nanoparticle top is clearly revealed by the computational and experimental results that show a negligible amount of carbon in the nanoparticle region in contact with the nucleating cap. The described carbon composition profile inside the nanoparticle is accompanied by a well-defined shape evolution of the nanocatalyst driven by the various opposite forces acting upon it both from the substrate and from the nascent carbon nanostructure. This new understanding suggests that tuning the nanoparticle/substrate interaction would provide unique ways of controlling the nanotube synthesis.
, Burgos, J.
, Lin, P.
, Sharma, R.
and Balbuena, P.
Nanocatalyst shape and composition during nucleation of single-walled carbon nanotubes, RSC Advances, [online], https://doi.org/10.1039/C5RA21877B, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918667
(Accessed November 29, 2023)