Effect of calcium on the absorption of NO on char surface:A density functional theory study

The effect of calcium on the adsorption of NO on char surface was studied by using density functional theory. Periodic boundary graphene model was adopted to simulate the graphitic structure of char surface; the catalytic effect of calcium on NO adsorption was investigated by decorating the graphene surface with calcium atoms which have a coverage rate of 13.3%. The results demonstrated that NO is physically adsorbed on the pristine graphene surface, with a binding energy of -19.34 kJ/mol; after decorating the graphene surface with calcium atoms, the adsorption is turned into a chemical sorption with a binding energy of -206.02 kJ/mol, due to the transfer of electrons in 4s and 3d orbitals of Ca atom to the NO molecule.