STRUCTURES AND ELECTRONIC PROPERTIES OF A CO2P CLUSTER DEPOSITED ON THE RUTILE TiO2(110) SURFACE BY FIRST-PRINCIPLES CALCULATIONS

The structures and electronic properties of different Co2P-supporting configurations on the rutile TiO2(110) surface have been investigated by first-principles density functional theory (DFT) calculations. A number of possible structural candidates and adsorption sites have been considered, while the calculations are executed on periodic systems using slab model. Our results indicate that the O atoms on TiO2(110) turn out to be preferable for the cluster to adsorb by Co atoms, with the largest adsorption energy of 211.50 kJ/mol in the most favorable model. According to the Mulliken charge analysis, the Co2P cluster carries a significant positive charge after adsorption, due to the charge transfer occurring from the adsorbate to the substrate. Moreover, the frontier molecular orbital analysis shows that the cluster-surface binding occurs mostly through the interplay of filled Co 3d orbital with unoccupied eigenstates of surface localized on O 2p orbital, which can be also corroborated by the projected density of states investigations, while the lowest unoccupied molecular orbital is mostly contributed by Ti 3d orbital of the surface. In addition, of particular significance is that deposition of Co2P on the rutile TiO2(110) surface results in a small band gap narrowing vis-a-vis the pure surface, yielding a positive effect on catalytic activity.