吡啶在Ti、Zr、N掺杂石墨烯表面吸附的理论研究

Theoretical calculations of pyridine adsorption on the surfaces of Ti,Zr,N doped graphene

采用密度泛函方法,研究了Ti、Zr和N掺杂及本征石墨烯对柴油中典型碱性氮化物吡啶的吸附行为,讨论了相应的吸附能、吸附构型、马利肯电荷转移、差分电荷密度和态密度。结果表明,金属Ti、Zr掺杂能显著增强吡啶在石墨烯表面的吸附能,非金属N掺杂可略微增加吡啶和石墨烯表面间的吸附能。吡啶在不同原子修饰的石墨烯表面的吸附能大小顺序为Ti掺杂石墨烯>Zr掺杂石墨烯>N掺杂石墨烯>本征石墨烯,吡啶可与Ti、Zr掺杂石墨烯发生N−Ti、N−Zr和π−π作用,与N掺杂石墨烯、本征石墨烯发生N−N、C−N和π−π作用。进一步分析发现,吡啶和金属Ti、Zr掺杂石墨烯表面存在明显的电子转移和化学键的形成,而和非金属N掺杂石墨烯及本征石墨烯间并无化学键形成。吡啶与Ti、Zr掺杂石墨烯发生化学吸附,与N掺杂石墨烯、本征石墨烯发生物理吸附。吡啶更稳定的吸附在Ti、Zr掺杂石墨烯表面。

In this paper,the adsorption behavior of pyridine,a typical basic nitrogen compound in diesel oil,on Ti-doped,Zr-doped,N-doped and intrinsic graphene has been investigated by density functional methods.The corresponding adsorption energy,adsorption configurations,Mulliken charge transfer,differential charge density and density of states were discussed.The results show that doping graphene with metal atoms such as Ti or Zr can significantly obviously enhance the adsorption energy between pyridine and graphene surfaces,while non-metal N doping has a relatively minor effect.The magnitude of the adsorption energy of pyridine on the surfaces of graphene modified with different atoms follows the order:Ti-doped>Zr-doped>N-doped>intrinsic graphene.Pyridine interacts with Ti-or Zr-doped graphene through N−Ti,N−Zr andπ−πinteractions,while with N-doped and intrinsic graphene,it interacts via N−N,C−N andπ−πinteractions.There are significant electron transfer and chemical bond formation between pyridine and metal-doped(Ti,Zr)graphene surfaces,indicating chemical adsorption.However,there is no chemical bond formation with non-metal N-doped graphene and intrinsic graphene,suggesting physical adsorption in these cases.Overall,pyridine exhibits more stable adsorption on the surfaces of Ti,Zr-doped graphene.