The distribution of excess carriers and their effects on water dissociation on rutile (110) surface

Abstract

The excess carrier widely exists in the metal oxides, while its effect on the water splitting is still unclear. Here, the first-principle calculations were carried out to investigate how the effects of excess carriers affect the water dissociation on rutile (110). The result shows that the excess electron and hole play different roles in the reactions because of the distinct behaviors. The excess electron is easily to be trapped in the lattice Ti atom, and the trapped electron slightly changes the reaction barrier of water dissociation. However, the excess hole prefers to stick with the hydroxyl radical, which can obviously lower the energy barrier of water dissociation from 0.39eV to 0.24eV. The results further show that the dissimilar behaviors of excess electron and hole mainly come from their abilities of trapping and distinct interaction with proton in rutile TiO2. Such work helps to understand carrier’s distribution and its effect on water splitting, which should help to reveal the role of excess electron and hole in TiO2.