First-Principle and Aimd Calculations on Water Dissociation at W8O16/WO3–Oxygen Vacancy Interface

In this paper, water dissociation at W8O16/WO3–Oxygen Vacancy (Ovs) interface under the water-gas-shift atmosphere was studied using first-principle and ab initio Molecular Dynamics (AIMD) calculations. It was found that, for the adsorption and dissociation of H2O molecules, oxygen vacancy on the WO3 surface usually play an important role, that is the defects surface not only act as the anchoring site of W atoms catalytic activity, but also affect the structure and charge distribution of the foundation oxide cluster. In this process, the exposed W atoms which close to O vacancy sites in oxide create a favorable nanoscopic environment for the adsorption and dissociation of H2O molecules jointly with neighboring O atoms and resulted a low dissociation barrier. The low dissociation barrier can be attributed to the presence of oxygen-philic W atoms to stabilize the generated OH groups, and the presence of oxygen atoms on the surface of tungsten oxide clusters to accept the remaining H atoms. In addition, the presence of CO molecules promotes the dissociation of H2O molecules in the water-gas-shift (WGS) atmosphere.