2012/01/10 by Shuangxi Wang, Ping Zhang, Wang, Shuang-Xi +3
Chemical Engineering · Materials Science · #Catalysis and Oxidation Reactions #Catalytic Processes in Materials Science #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.1201.1974
openalex publication_date 2012/01/10 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The adsorption properties of isolated H2O molecule on stoichiometric and reduced (with on-surface oxygen vacancy) ceria(1111) surfaces at low coverage are theoretically investigated by using density-functional-theory+U calculations and ab initio molecular dynamics simulations. We identify the most stable adsorption configurations on these two kinds of surfaces, which form two hydrogen bonds between the water molecule and the oxide surface. The electronic structures indicate that the hybridization of the molecular orbitals of water and surface-layer O-2p states dominates the interactions between adsorbate and substrate. The barrier of 0.51 eV for water diffusion on the stoichiometric surface implies the inertia of water unless up to a high temperature of 600 K, which is confirmed by the molecular dynamics simulations. For the reduced surface, we find that the oxygen vacancy obviously enhances the interaction. Moreover, it is facilitated for water to dissociate into H and OH species with a hydroxyl surface formed, instead of oxidizing the reduced surface with the production of hydrogen gas. In addition, the molecular dynamics simulations at low temperature 100 K confirm the dissociation process.