The adsorption of CO on regular and defect sites of MgO(001) surface was studied theoretically by using embedded cluster models by DFT/B3LYP method. The value of embedded point charges was determined by the charge self-consistent technique. The calculated results indicated that CO adsorption energy on the regular site of MgO(001) surface could agree well with the recent experimental data. The frequency shifts of CO for regular five-coordinated terrace, low 4-coordinated edge and 3-coordinated corner sites, via C bound down on cationic centers of MgO(001) surface were also satisfactorily close to the values of experiment. At the same time, the adsorption of CO on MgO(001) surface with neutral and charged O vacancies, Fs, Fs+ and Fs2+ centers, was investigated whose results show that MgO(001) surface with neutral O vacancy had probably the good catalysis structure for CO adsorptive-decomposition. This was consistent with a previous study, performed by using a different method. By analyzing the bond component of Mg–C, it was found that the essential reasons why C–O bond strength was weaken or strengthen were the competitive results of 4σ* lone pair electrons and 5σ electrons of CO transferring from the adsorbate to substrate simultaneously.

CO Adsorption on MgO(001) Surface with Oxygen Vacancy and its Low-Coordinated Surface Sites - Embedded Cluster Model Density Functional Study Employing Charge Self-Consistent Technique. Y.Xu, J.Li, Y.Zhang, W.Chen: Surface Science, 2003, 525[1-3], 13-23