Reactive Molecular Dynamics Study on the Growth Mechanism of Nitrogen-Doped Graphene in an Arc Plasma Environment.

CONTEXT

This study systematically investigates the growth mechanism of nitrogen-doped graphene in a plasma environment, with a particular focus on the effects of temperature and hydrogen radicals on its structural evolution. The results reveal that, at 3000 K, the formation of nitrogen-doped graphene proceeds through three stages: carbon chain elongation, cyclization, and subsequent condensation into planar structures. During this process, nitrogen atoms are gradually incorporated into the carbon network, forming various doping configurations such as pyridinic-N, pyrrolic-N, and graphitic-N. An increase in temperature accelerates the reaction kinetics and cluster growth, but concurrently reduces the stability of nitrogen incorporation. Hydrogen radicals play a dual role: they help maintain the planar structure and suppress the curling of carbon clusters; however, excessive hydrogen radicals compete for edge-active sites, thereby inhibiting nitrogen doping efficiency. This work provides deeper insight into the growth mechanism of nitrogen-doped graphene and offers theoretical guidance for its efficient and controllable synthesis.

METHODS

In this study, we employed molecular dynamics (MD) simulations using the LAMMPS software package combined with the ReaxFF reactive force field to systematically investigate the growth mechanism of nitrogen-doped graphene in a plasma environment, as well as the effects of temperature and hydrogen radicals on its structural evolution. All simulations were performed in the NVT ensemble with a time step of 0.1 fs and a total simulation duration of 15,000 ps. To reduce variability and enhance the reliability of the results, each simulation was carefully repeated three times under identical conditions for subsequent statistical analysis.