论文部分内容阅读
采用密度泛函理论(DFT)研究了氧吸附后Pt/Cu(001)表面合金的原子结构和表面性质.计算结果表明,在Pt/Cu(001)-p(2×2)-O表面最稳定结构中,衬底表面原子层不发生再构,氧原子吸附于4重对称的Pt原子谷位,每个氧原子吸附能约为2.303 eV.吸附结构的Cu—O和Pt—O键键长分别为0.202和0.298 nm,氧原子的吸附高度ZCu—O约为0.092 nm.吸附前后Pt/Cu(001)-1ML(monolayer)表面合金的表面功函数分别为4.678和5.355 eV.吸附表面氧原子和衬底的结合主要来自氧原子2p轨道和衬底金属原子d轨道的杂化作用,氧原子吸附形成的表面电子态主要位于费米能级以下约-2.7 eV处.
The atomic structure and surface properties of Pt / Cu (001) surface alloy after oxygen adsorption were investigated by using density functional theory (DFT). The calculated results show that the surface structure of Pt / Cu (001) In the stable structure, the atomic layer of the substrate is not reconstructed, and the oxygen atoms are adsorbed to the valley of 4-symmetric Pt atoms, and the adsorption energy of each oxygen atom is about 2.303 eV. The Cu-O and Pt-O bonds (0.202 and 0.298 nm, respectively) and the oxygen atom adsorption height (ZCu-O) is about 0.092 nm.The surface work function of Pt / Cu (001) -1ML monolayer before and after adsorption are 4.678 and 5.355 eV, The bond between the atom and the substrate is mainly due to the hybridization of the 2p orbitals of the oxygen atoms and the d orbitals of the substrate metal atoms. The surface electronic states formed by oxygen atom adsorption are mainly located at about -2.7 eV below the Fermi level.