Cluster modeling of chemisorption and reactions on metal oxide surfaces

The research on the cluster modeling of chemisorption and reactions on metal oxide surfaces in our group has been reviewed. Three principles, namely, neutrality principle, stoichiometrical principle and coordination principle were proposed for building up cluster models of metal oxides. Good correlation between the topologic parameters N-c (beta(c)), N-a (beta(a)) and N-d (beta(d)) with the stability of clusters has been shown. The problem of how the ways of embedding affect the calculated electronic properties of the substrate clusters and the adsorption properties has been investigated. Based on these, we proposed an SPC model, which is a stoichiometric cutout cluster embedded in a spherically expanded point charge surrounding with charges being self-consistently determined. We have successfully applied the SPC model to a variety of important systems, including H-2/ZnO, O/MgO, NO/MgO, N2O/MgO, N2O/Li/MgO, CO/MgO and CO/NiO.