Electronic properties of the VO2(0 1 1) surface: density functional cluster calculations

This paper reviews electronic properties of the VO2(0 1 1) surface. In particular it discusses the nature of surface V–O bonding. In addition, the electronic states of the structurally different surface oxygen sites are described and correlated with their catalytic properties. The calculations are performed by means of the ab initio DFT method. The vanadium dioxide surface is modeled using clusters of different sizes. Results of the study confirm the bonding in vanadium dioxide as a mixture of ionic and covalent character. Further, nucleophilic properties of structurally non-equivalent surface oxygen sites are found to increase with their coordination number. It is shown that in order to describe 5- and 6- fold vanadium centers correctly clusters containing two physical layers are required as models.