The structure of higher defective ZnO (1 0 (1)over-bar 0)

The surface structure of clean and defective ZnO(1010) have been studied using ab initio plane wave density functional theory. Two models of surface defects have been examined; an oxygen vacancy within the surface Zn-O dimer and an oxygen vacancy in the second layer of the material. Previous models of CO oxidation on this surface have invoked the formation of isolated second layer defects. In the current study we show that the formation of such a defect costs 1.01 eV more energy than the formation of a vacancy within the dimer bond and hence models of catalytic activity that invoke the formation of isolated second layer defects need to be re-examined. (C) 2003 Elsevier Science B.V. All rights reserved.