A Theoretical Study of Water Adsorption and Decomposition on the Low-Index Stoichiometric Anatase TiO2 Surfaces

Water adsorption and decomposition on the low-index anatase TiO2 surfaces were investigated by the periodic density functional theory calculations. The reaction pathway between water molecule adsorption and dissociative adsorption was determined by using the method of complete linear synchronous transit/quadratic synchronous transit. The existence of Brønzed–Evans–Polanyi relationships for the decomposition reaction of water on TiO2 surfaces was revealed. The results showed that the water decomposition reaction is a surface-structure-sensitive process, and it is determined not only by the surface energy but also by the surface properties. On these low-index surfaces, the chemical activity for the water decomposition reaction decreases in the order (001) > (103)f > (100) > (110) > (103)s > (101). The surfaces can be divided into two groups, according to the magnitude of additional surface dipole moment, that obey the Brønzed–Evans–Polanyi relationship.