钙元素对焦炭表面NO吸附行为的影响:密度泛函理论研究

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

采用密度泛函理论研究了Ca元素对焦炭表面NO吸附行为的影响。使用周期性石墨烯模型近似模拟实际焦炭表面的石墨化结构,并在石墨烯表面装饰Ca原子(按质量计Ca原子覆盖率为13.3%),考察了Ca元素对焦炭表面NO吸附的催化作用。计算结果表明,NO分子在纯净石墨烯表面的吸附属于物理吸附,结合能仅为-19.34 k J/mol;石墨烯表面掺入Ca原子后,由于Ca原子4s轨道和3d轨道的电子转移到NO分子,结合能显著提高至-206.02 k J/mol。

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.