单原子催化剂Ir_(1)/MoS_(2)表面上NH_(3)吸附理论研究

Theoretical studies of of NH_(3)adsorption on the surface of monatomic catalyst Ir_(1)/MoS_(2)

采用密度泛函理论与周期性平板模型相结合的方法,对单原子催化剂Ir在MoS_(2)表面的fcc、hcp两个吸附位和NH_(3)在单原子催化剂Ir_(1)/MoS_(2)上的四个吸附位的6种吸附模型进行了构型优化和能量计算,得到了Ir原子最稳定的吸附位以及NH_(3)的优势吸附位;并对最佳吸附位进行了电荷密度差和态密度分析.结果表明:Ir_(1)/MoS_(2)体系最稳定的是Ir原子在MoS_(2)的三重空位(hcp);NH_(3)的优势吸附构型为倾斜结构(atop),NH_(3)与体系表面成键,属于化学吸附;NH_(3)与体系Ir_(1)/MoS_(2)的吸附成键主要是通过3a1轨道与Ir原子的5S、5dyz轨道相互杂化产生的.

The density functional theory(DFT)combined with periodic plate model was used to optimize the configuration and calculate the energy of six adsorption models of two adsorption sites(fcc and hcp)of Ir on MoS_(2)and four adsorption sites of NH_(3)on Ir_(1)/MoS_(2).The best adsorption sites were analyzed by charge density difference and density of states.The results show that:the most stable of Ir_(1)/MoS_(2)system is the triple vacancy(hcp)of Ir atom in MoS_(2);the dominant adsorption configuration of NH_(3)is atop,NH_(3)is bound to the surface of the system,which belongs to chemical adsorption;The adsorption bonding between NH_(3)and Ir_(1)/MoS_(2)is mainly due to the hybridization between 3a1 orbital and 5s、dyz orbital of Ir atom.