Controllable dissociation of H2O on a CeO2(111) surface

Abstract

Splitting water on metal oxide surfaces plays a key role in surface catalytic reactions. Continuously tuning the molecular/dissociative states of H₂O can be expected to achieve controllable catalysis. In this work, we propose a promising method to split water on a CeO₂(111) surface and uncover the dissociation mechanism. According to first-principles calculations, we demonstrate that tensile strain facilitates water dissociation on the CeO₂(111) surface due to the enhancement of hybridization between the 4f states of surface Ce and the 2p states of the dissociated H₂O. More importantly, strain-induced water dissociation could also apply to other metal oxide surfaces, such as PaO₂(111), ThO₂(111), and CaO(100). It is proposed that different behaviors of the oxygen 2p band center shift for molecular and dissociative H₂O are responsible for tensile strain-induced water dissociation on metal oxide surfaces. The results indicate that Ag(111) or Au(111) can serve as substrates to realize water dissociation on ultra-thin CeO₂(111) films. Our studies provide an effective approach for tuning the surface reactions of metal oxide surfaces by modulating lattice parameters.