关于单层1T-MoS_2吸附元素汞的密度泛函理论研究（英文）

Density functional theory study of the adsorption of elemental mercury on a 1T-MoS_2 monolayer

目的:探索1T-MoS_2(多型结构的二硫化钼)的除汞机制。方法:1.采用密度泛函理论(DFT)分析Hg^0在1T-MoS_2单层上的吸附机理。2.考察1T-MoS_2的不同吸附位置。3.对不同的吸附构型,研究电子吸附前后的变化,从而进一步了解吸附过程。结论:1.化学吸附是Hg原子与1T-MoS_2单层吸附的主导因素。同时,在所有可能的吸附位置中,T_(Mo)(在钼原子上方)的位置是最强烈的吸附构型。2.汞(Hg)原子在1T-MoS_2单层上的吸附受邻近的硫(S)和钼(Mo)原子的影响。3.吸附的汞(Hg)原子在1T-MoS_2的TMo位置上会被氧化,其吸附能为-1.091 eV。4.从局部态密度(PDOS)分析来看,Hg原子和1T-MoS_2表面之间的相互作用是由汞(Hg)原子的d轨道与硫(S)原子的s轨道及钼(Mo)原子的p轨道和d轨道重叠所致。

Elemental mercury has become a global concern because of its significant impact on human health and the ecosystem. A lot of effort has been put towards the removal of elemental mercury from the 2 H-Mo S_2（prismatic structure of Mo S_2）. However, the mechanism of 1 T-Mo S_2（polytype structure of Mo S_2） in Hg^0 capture remains unexplored. In this study, density functional theory（DFT） was adopted to investigate the adsorption mechanism of Hg on a 1 T-Mo S_2 monolayer. The different possible adsorption positions on the 1 T-Mo S_2 were examined. For different adsorption configurations, the changes in electronic property were also studied to understand the adsorption process. The results elucidated that chemisorption dominates the adsorption between Hg^0 atoms and the 1 T-Mo S_2. It was found that the T_（Mo）（on top of the Mo atom） position is the strongest adsorption configuration among all the possible adsorption positions. The adsorption of Hg^0 atoms on the 1 T-Mo S_2 monolayer is influenced by adjacent S and Mo atoms. The adsorbate Hg^0 atom is found being oxidized on the TMo position of the 1 T-Mo S_2 with an adsorption energy of-1.091 e V. From the partial density of states（PDOS） analysis of the atoms, the strong interaction between Hg^0 and the 1 T-Mo S_2 surface is caused by the significant overlap among the d orbitals of the mercury atom and the s orbital of the S atom and p and d orbitals of the Mo atom.