Insights into adsorption, diffusion, and reactions of atomic nitrogen on a highly oriented pyrolytic graphite surface

To gain insight into the nitrogen-related gas-surface reaction dynamics on carbon-based thermal protection systems of hypersonic vehicles, we have investigated adsorption, diffusion, and reactions atomic nitrogen, N(4S), (0001) face graphite using periodic density functional theory with a dispersion corrected functional. The nitrogen is found to bind pristine at bridge site, barrier 0.88 eV for diffusing an adjacent site. Its adsorption energy defect sites significantly higher, while that between graphene layers lower. formation N2 via Langmuir–Hinshelwood (LH) Eley–Rideal (ER) mechanisms was also investigated. In LH pathway, recombinative desorption proceeds transition state relatively low (0.53 eV). addition, there metastable surface species, which capable trapping nascent temperatures as result large disposal N–N vibration. desorbed highly excited in both its translational vibrational degrees freedom. ER direct fast, it leads translationally internally N2. Finally, CN from site calculated be endoergic by 2.75 eV. These results are used rationalize recent molecular beam experiments.