title: Carbon nanotube nucleation driven by catalyst morphology dynamics.
abstract: In situ observation of the carbon nanotube nucleation process accompanied by dynamic reconstruction of the catalyst particle morphology is considered within a thermodynamic approach. It reveals the driving force for the detachment of the sp(2)-carbon cap, so-called lift-off-a crucial event in nanotube growth. A continuum model and detailed atomistic calculations identify the critical factors in the lift-off process: (i) catalyst surface energy, affected by the chemisorbed carbon atoms at the exterior surface of the catalyst, exposed to the carbon feedstock; and (ii) the emergence of a pristine, high-energy facet under the sp(2)-carbon dome. This further allows one to evaluate the range of carbon feedstock chemical potential, where the lift-off process occurs, to be followed by emergence of single-walled nanotube, and provides insights into observed catalyst morphology oscillations leading to formation of multiwalled carbon nanotubes.
authors.affiliation: Honda Research Institute USA Inc., Columbus, Ohio 43212, United States.
authors.forename: Elena
authors.initials: E
authors.lastname: Pigos
authors.forename: Evgeni S
authors.initials: ES
authors.lastname: Penev
authors.forename: Morgana A
authors.initials: MA
authors.lastname: Ribas
authors.forename: Renu
authors.initials: R
authors.lastname: Sharma
authors.forename: Boris I
authors.initials: BI
authors.lastname: Yakobson
authors.forename: Avetik R
authors.initials: AR
authors.lastname: Harutyunyan
mesh_terms: D002384:Catalysis; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D037742:Nanotubes, Carbon