First-principles investigation of electrified monolayered MoS2/water interface

Abstract

We investigate electrochemical properties of electrified MoS${}_2$/water interface under applied bias potential. We show that water molecules rearrange depending on whether the surface is positively or negatively charged. A positive charge pulls water’s oxygen atoms closer to the surface, while extra electrons make water flip so that hydrogen atoms get nearer the surface. Abrupt changes are observed in the double layer charge and in the capacitance evolution as a function of bias potential and are explained by semiconductor nature of the MoS${}_2$ material. Overall, our findings confirm earlier results on the water dynamics at electrified metal–water interfaces and highlight that using explicit and hybrid modeling approaches helps to capture the fine details of electrochemical processes at solid/liquid interfaces.