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.