The role of S and Mo doping on the dissociation of water molecule on FeOCl surface: Experimental and theoretical analysis

FeOCl is widely used in cathode of lithium ion battery, matrix material and reaction catalyst. In which, the interactive behavior of H2O on FeOCl surface is closely related with the property of FeOCl materials. In this study, the influences of S and Mo doping on H2O molecule adsorption and dissociation on FeOCl (010) were explored by DFT calculations and experiments. Both calculations and experimental proved S and Mo doping promote the adsorption and dissociation of H2O molecule on FeOCl (010) surface with different process mechanisms. The surface electronegativity decreases slightly due to S doping, which reduces the repulsion to H2O molecule and lower the adsorption energy compared with clean surface. While, after forming stable adsorption structure, S doping promotes the dissociation of H2O by changing the electrons distribution in H2O and competing the shared electrons to weak the O–H bond strength. In contrast, Mo doping enhances the electropositivity of the surface, which is more conducive to the molecular adsorption reaction and more exothermic via coulombic attraction. For dissociative adsorption, the strength of O-H bond is enhanced, and the dissociation process is inhibited by Mo doping due to the electrons polarization in H2O molecule. Furthermore, S and Mo atoms are proved to be incorporated into the FeOCl lattice which enhance of H2O dissociation on doped FeOCl nanosheets surface. This study presents a microscopic insight for effects of S and Mo doped FeOCl surface on H2O molecule behaviors, while provides a theoretical basis for further research of the FeOCl surface water.