空位缺陷及B掺杂石墨烯吸附Co^(2+)的第一性原理研究

First principles study on adsorption of Co^(2+)on vacancy-defected and boron-doped graphene

采用第一性原理方法研究了本征石墨烯、硼掺杂石墨烯、空位缺陷石墨烯、空位硼掺杂石墨烯对Co^(2+)离子的吸附作用。通过计算、分析上述不同石墨烯模型吸附Co^(2+)后几何结构、吸附能、电荷转移量及能带结构的变化,发现本征石墨烯与Co^(2+)虽能发生吸附,但吸附效果差;硼掺杂与空位缺陷使石墨烯与Co^(2+)之间的吸附能增大,并使石墨烯能带产生带隙,显著提高了石墨烯对Co^(2+)的吸附性。吸附后的体系态密度分析表明,三种改性石墨烯均与Co^(2+)的态密度曲线发生明显重叠,表明相互之间发生了化学吸附。其中空位缺陷石墨烯对Co^(2+)的吸附性能最优,其次是空位硼掺杂石墨烯,表明空位缺陷石墨烯和空位硼掺杂石墨烯可作为Co^(2+)的检测和吸附去除材料。

On the basis of first-principles calculation,the adsorption performance of Co^(2+)ions on pristine graphene,boron-doped graphene,vacancy-defected graphene,and boron-doped vacancy-defected graphene was investigated.By computing and analyzing the geometric structure,adsorption energy,charge transfer and band structure of the above mentioned four types of graphene after Co^(2+)adsorption,we can find that although there exists an adsorption interaction between pristine graphene and Co^(2+),the effect of the adsorption is poor.Both boron doping and vacancy defects can increase the adsorption energy between graphene and Co^(2+),and result in a bandgap in the band structure of graphene,greatly enhancing the adsorption effect of graphene to Co^(2+).Analysis on the density of states of the adsorption system of graphene and Co^(2+)demonstrates that there is a strong coupling between Co^(2+)and the three types of modified graphene,indicating the occurrence of chemical adsorption between them.Among the three types of modified graphene,the vacancy-defected graphene has the strongest adsorption to Co^(2+),followed by boron-doped vacancy-defected graphene.This indicates that vacancy-defected graphene and boron-doped vacancy-defected graphene can be used for detecting and removing Co^(2+)ions by adsorption.