Structure and Activity Relationship for Single-Walled Carbon Nanotube Growth Confirmed by In-Situ observations and Modeling
The structure and phase transformation of cobalt (Co) catalyst, during single walled carbon nanotube (SWCNT) growth, is elucidated for inactive, active and deactivated nanoparticles by in-situ imaging using an environmental transmission electron microscope. During nanotube growth, the structure was analyzed using Miller indicies to determine the types of planes that favor anchoring or liftoff of nanotube from the Co catalyst. Density functional theory was further applied to model the catalyst interactions to compare the work of adhesion of the catalyst’s faceted planes to understand the interactions of different Miller planes with graphene structure. Through in-depth studies of multiple distinct Co nanoparticles, we establish the dominant nanoparticle phase for SWCNT growth. In addition, we identified the preferred lattice planes and a threshold for work of adhesion to allow the anchoring and liftoff of SWCNT.