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采用密度泛函理论(Density Functional Theory DFT)研究Au(100)和Au(111)表面含有不同Pd构型时表面的形成能.结果表明,非连续Pd构型的形成能较连续Pd构型的低,在表面易形成,其中第二临位Pd对构型被证实是乙烯与醋酸结合生成醋酸乙烯反应中催化活性最高的构型.随后计算CO在不同表面Pd原子的顶位吸附能和Pd原子的d带中心,结果显示表面Pd原子与相邻金原子之间几乎没有电子传递,并且PdAu(111)表面的Pd原子d带中心随周围Au原子个数的增加而远离费米能级,伴随着CO在其上吸附能的减小,但是同样的趋势在PdAu(100)表面不存在.最后,通过计算,CO在金属表面的吸附机理为CO成键轨道5σ的电子传递给Pd原子的d带,而Pd原子的d带电子又反馈回CO的反键轨道2π*.
Density Functional Theory (DFT) was used to investigate the formation energies of Au (100) and Au (111) surfaces with different Pd configurations. The results show that the formation of discontinuous Pd conformations is stronger than that of Pd Low, easy to form on the surface, in which the second Pro Pd configuration confirmed by ethylene and acetic acid to generate vinyl acetate reaction of the highest catalytic activity.Further calculation of CO adsorption Pd atoms on different top surface adsorption energy and Pd The results show that there is almost no electron transfer between the surface Pd atoms and the adjacent gold atoms, and the d center of the Pd atom on PdAu (111) surface is far away from the Fermi level as the surrounding Au atoms increase. With the decrease of CO adsorption energy, but the same tendency does not exist on the surface of PdAu (100) .Finally, the adsorption mechanism of CO on the metal surface is calculated by the electron transfer of 5σ of CO bond to Pd atom d band, and d atoms of the Pd atom are fed back to the antibonding orbit 2π * of CO.