(460b) A Simulation Study of the Effect of CO and CO2 Adsorption on the Iron Particle Formation and Nanotube Nucleation for a Floating Catalyst System

Single-walled carbon nanotubes (SWCNTs) are seamless cylinders of graphene that have been at the forefront of nanotechnology research for the past two decades. They possess a range of exceptional properties including high strength (~37 GPa), thermal conductivity (~3500 W/m/K) and ballistic electronic transport. Importantly, they can have semiconducting, semi-metallic, or metallic conductivity depending on their chiral angle (χ), i.e. the angle between the tube axis and the edge of the graphene lattice. Recent progress in floating catalyst chemical vapor deposition (FC-CVD) using iron have shown the ability of this particles to produce highly selective chiral nanotubes with diameter profiles in the range of 1 nm to 4 nm. Iron (Fe) nanoparticles have attracted great interest due to their potent magnetic and catalytic properties which strongly depend on the structures and morphologies.

In this work, we use molecular dynamics to simulate a FC-CVD process using carbon monoxide (CO) as main carbon source. Additionally, DFT simulations help to quantify the strength of interaction and locate preferred adsorption sites for different metal compositions. A detailed knowledge of the structure and dynamic evolution in the composition for the iron particles during the production of carbon nanotubes (CNTs) is important for understanding many surface phenomena such as adsorption, oxidation, and catalytic reactions and their effects on nanotube nucleation and growth.