Conversion of N2O to N2 on MgO （001） Surface with Vacancy： A DFT Study
摘要
The adsorption and decomposition of NzO at regular and defect sites of MgO (001) surface have been studied using cluster models embedded in a large array of point charges (PCs) by DFT/B3LYP method. The results indicate that the MgO (001)surface with oxygen vacancies exhibits high catalytic reactivity toward N2O adsorptive-decomposition. It is different from the regular MgO surface or the surface with magnesium vacancies.Much elongation of O—N bond of N2O after adsorption at oxy-gen vacancy site with O end down shows that O—N bond has been broken with concurrent production of N2, leaving a regu-lar site instead of the original oxygen vacancy site (F center ).The MgO (001) surface with magnesium vacancies hardly ex-hibits catalytic reactivity. It can be concluded that N2O dissoci-ation likely occurs at oxygen vacancy sites of MgO (001) sur-face, which is consistent with the generally accepted viewpoint in the experiments. The potential energy surface (PES) reflects that the dissociation process of N2O does not virtually need to surmount a given energy barrier.