Theoretical Study on the Surface Energy of TiO2 Rutile(110)

The density functional theory and pseudopotential method were employed to investigate the TiO_2 rutile(110)surface energy corresponding to the defect concentration.It is shown that the surface energy is dependent on the defect percentage,i.e.,the zero defect surface possesses the lowest surface energy and the 100.0% defect surface possesses the highest surface energy.On the other hand,when we added O atoms to the fivefold-coordinate Ti4+ sites of the perfect surface with a defect below 50%,there is little change of the surface energy,although the perfect surface still has the lowest surface energy.When we added more O atoms to these sites,the surface energy becomes higher.