N2O decomposition on Ti3O6 deposited on anatase(1 0 1) from first-principles calculations: The role of oxygen vacancy†

Polarons induced by oxygen vacancy play a key role in many reactions on the reduced transition metal oxides. In this study, based on DFT + U calculations, we addressed the N2O decomposition on Ti3O6 cluster deposited on anatase(1 0 1). In the first half of the cycle, N2O adsorbed on the titanium atom of the cluster, resulting in the formation of N2 and O2 and oxygen vacancy. In the second one, another N2O interacted with the oxygen vacancy site to recreate the cluster, leaving an N2 molecule. The total dissociation energy of two subsequently adsorbed N2O molecules into 2 N2 and O2 is −0.15 eV. It is found that two polaron states appear in the presence of the oxygen vacancy. Based on the N2O adsorption energies, we discover that N2O decomposition take place in a geometry-dependent manner. In other words, among two different configurations proposed for N2O adsorption on Ti3O6@anatase(1 0 1) and Ti3O5@anatase(1 0 1) systems, only the decomposi- tion via the O-Ti pathway on Ti3O5@anatase(1 0 1) leads to the exothermic effect of −1.41 eV and energy barrier of 1.07 eV, which facilitates the decom- position of N2O on Ti3O5@anatase(1 0 1). Therefore, in order to obtain N2O dissociation on this cluster, the generation of the oxygen vacancy is crucial.