过渡金属Pd掺杂AsP结构及其吸附甲醛和一氧化碳的性能研究

基于第一性原理方法，研究了单层本征磷砷AsP和过渡金属钯（Pd）掺杂磷砷AsP的结构，并对比研究了本征和掺杂后的AsP吸附甲醛（HCHO）和一氧化碳（CO）气体分子的稳定性、能带结构、态密度以及电荷差分密度。研究结果表明：经Pd掺杂后AsP由半导体转变为导体；本征AsP吸附一氧化碳最稳定的位置为P-As键顶上，吸附甲醛最稳定的位置为P原子顶上；本征吸附时气体分子与基底之间的距离在3 Å左右，气体分子与基底之间未形成化学键。过渡金属Pd原子掺杂AsP后形成两种结构，分别为Pd原子替换超胞结构中的As原子或P原子。两种掺杂结构分别吸附一氧化碳或甲醛气体分子时，除了Pd原子替换AsP中的As原子形成的结构吸附甲醛的吸附能未明显增加外，其余掺杂结构吸附一氧化碳或甲醛的吸附能和电荷转移较本征吸附时均显著增强，吸附CO分子时，C原子与Pd原子之间形成了化学键。特别是，Pd原子替换AsP中的P原子形成的结构对一氧化碳和甲醛气体分子的吸附性能明显强于Pd原子替换AsP中的As原子所形成的结构。

A study of Pd-doped AsP Structure and its Adsorption properties for Formaldehyde and Carbon Monoxide

The electronic structure properties and adsorption ability of pristine AsP and Pd-doped AsP are systematically studied using the first principles method. The structures, band structures, densities of states and charge densities of pristine AsP monolayer and Pd-doped AsP monolayer are investigated comparatively. Especially, the abilities of formaldehyde (HCHO) and carbon monoxide (CO) adsorptions are compared between pristine AsP and Pd-doped AsP. The study indicates that Pd-doping changes the AsP from semiconductor to conductor. The most stable position of the pristine AsP adsorbing CO is on the top of P-As bond, and the most stable position of the pristine AsP adsorbing HCHO is on the top of P atom. The distance between gas molecules and substrate is about 3Å, no bond is formed between gas molecule and substrate. The transition metal Pd atom doped into AsP form two kinds of structures, which are Pd atom replacing As atom and Pd atom replacing P atom in the supercell structure. The two kinds of doping structure adsorb CO or HCHO gas molecules respectively, the adsorption energy and charge transfer of CO or HCHO on the other doped structures are significantly higher than those on the pristine adsorption except that the adsorption energy of HCHO on the structure formed by Pd atom replacing As atom in ASP is not significantly increased. When Pd-doped AsP structure adsorbs CO molecules, chemical bond is formed between C atom and Pd atom. Especially, for the Pd-doped AsP structures, the structure formed by Pd atom replacing P atom in AsP has better gas adsorption ability for carbon monoxide (CO) and formaldehyde (HCHO) than that of structures formed by Pd atom replacing As atom in AsP.