Molecular Dynamic Simulation of Water/ Peroxide Reaction on Defective Ceria (110) Surface

Car-Parrinello molecular dynamic simulations are used to show that 110 ceria surface with vacancy sites is suitable to dissociate water and/or peroxide at the solvent/solid interface. We present density functional theory and ab initio molecular dynamics simulations of water in the liquid phase interacting with vacancy defects at (110) ceria surface. Water molecule approaches the vacancy from the water solvent observed to transfer a proton to a nearby oxygen. The formed hydroxide weakly binds to the Ce-vacancy atom after which it diffuses back to the solvent in a short period of simulation time (~1 pse). However, this mechanism is more complex in the case of peroxide solvent. Two possible pathways are observed as a peroxide molecule approaches the vacancy. The first pathway involves peroxide dissociation into tow hydroxides that diffuse back to the peroxide solvent. While the second pathway involves a dual proton transfer to oxygen atoms near the vacancy while O₂ diffuses freely to the peroxide liquid. These simulations highlight the role of surface defects in providing suitable adsorption sites that accelerate the dissociation of water / peroxide species at the liquid/solid interface.