Adsorption of small hydrocarbons on pristine, N-doped and vacancy graphene by DFT study

In this paper, the adsorption mechanisms between different species (CH₃, CH₄, C₂H₂, C₂H₄, C₂H₆, and C₆H₆) and the carbon-based materials (pristine graphene, N-doped graphene, and vacancy graphene) during the chemical vapor infiltration process were systematically studied using the density functional theory. The optimized adsorption configurations were obtained by using Dmol³ code in Material Studio. The adsorption energies, Mulliken atomic charges, density of states, and charge density differences of the adsorption process were analyzed. It showed that the CH₃ is chemisorbed, while the other species (CH₄, C₂H₂, C₂H₄, C₂H₆, and C₆H₆) are weak physisorbed on pristine graphene, N-doped graphene and vacancy graphene. In addition, the introduction of nitrogen dopant and vacancy defect into the pristine graphene does not significantly affect the adsorption mechanisms between small hydrocarbons and graphene.