噻吩在M(111)(M=Pd,Pt,Au)表面的吸附(英文)

采用密度泛函理论(DFT),选取DMol3程序模块,对噻吩在M(111)(M=Pd,Pt,Au)表面上的吸附行为进行了探讨.通过对噻吩在不同底物金属上的吸附能、吸附构型、Mulliken电荷布居、差分电荷密度以及态密度的分析发现,噻吩在Pd(111)面上的吸附能最大,Pt(111)面次之,Au(111)面最小.吸附后,噻吩在Au(111)面上的构型几乎保持不变,最终通过S端倾斜吸附于top位;噻吩在Pd(111)及Pt(111)面上发生了折叠与变形,环中氢原子向上翘起,最终通过环平面平行吸附于hollow位.此外,噻吩环吸附后芳香性遭到了破坏,环中碳原子发生sp3杂化,同时电子逐渐由噻吩向M(111)面发生转移,M(111)面上的部分电子也反馈给了噻吩环中的空轨道,这种协同作用最终导致了噻吩分子稳定吸附于M(111)面.

Adsorption of Thiophene on M(111) (M=Pd,Pt, Au) Surfaces

The adsorption of thiophene on Pd(111), Pt(111), and Au(111) surfaces was investigated by periodic density functional theory (DFT) calculations at the GGA/PW91 level. The results showed that the adsorption energies of thiophene on the different surfaces following the order Pd(111)>Pt(111)>Au(111). The adsorption structure on the Au(111) surface showed almost no change, and the most stable adsorption structure was tilted adsorption on the top site through the S atom of thiophene. For the Pd(111) and Pt(111) surfaces, the most stable adsorption structure was parallel adsorption to the hollow site through the ring plane of thiophene. After adsorption, the H atom of thiophene moved upward and the structure of thiophene was distorted and folded. The aromaticity of thiophene was disrupted and the C atoms were characteristic of sp³ hybridization. Furthermore, the electrons of the M(111) surfaces and thiophene were redistributed after adsorption. The electron transfer from thiophene to the M(111) surfaces was in the order Pd(111)>Pt(111)>Au(111). The electrons of the M(111) surfaces were also back-denoted to the empty orbitals of the thiophene molecule. These processes eventually lead to the adsorption of thiophene on the M(111) surfaces.