Investigating the role of cationic vacancy on the MgO (0Â 0Â 1) defect surface: Embedded cluster models study

The adsorption and dissociation of Cl2 at different magnesium vacancy sites (V, V− or V2− center) of the MgO (0 0 1) defect surface have been investigated using density functional theory coupled with embedded cluster models. It is rather interesting to find that the magnesium vacancy sites at the edge or corner exhibit quite high surface reactivity toward the dissociation of Cl2. The dissociation process proceeds without energy barrier as reflected by the calculated potential energy curve. Whereas, the case is different for the magnesium vacancy sites at the terrace, i.e., no surface reactivity toward the dissociation of Cl2. Meanwhile, the results herein are compared to those at “electron-rich” oxygen vacancy sites. The present findings illustrate that the low-coordinated magnesium vacancy sites on the MgO (0 0 1) surface should be attached to importance in the catalysis community because they can act as active centres in adsorption and dissociation processes of technological importance. We believe that these results would be particularly beneficial for understanding the chemical reactivity of MgO defect surfaces.