Water adsorption behaviors of high index polar surfaces in ZnO

Abstract

The density functional theory method study is performed to investigate the adsorption structures and mechanisms of water adsorption on ZnO high index polar surfaces. It is found that compared to the nonpolar 101¯0 and (0001) surfaces, high index polar surfaces present higher ability to adsorb water molecules. The dissociative adsorption configurations are energetically more favorable than the molecular adsorption ones, i.e., the adsorbed water molecule would like to decompose into a hydroxyl group and a H atom on high index polar surfaces. The structural calculations and electronic properties suggest that the electron counting rule plays an important role in determining the energetically favorable configurations. This detailed and systematic work not only improves our understanding of the water adsorption on high index polar surfaces, but also it may ultimately aid the applications of nanostructures coated by high index polar surfaces.