Recent advances in calculating potential of zero charge and Helmholtz capacitance of metal/aqueous solution interfaces from ab initio molecular dynamics

The surface charge density is a crucial property of the electric double layer. It determines the strength of the electric field, the water orientation, and ion hydration structure at interface and thus has strong impact on the performance of electrocatalytic reactions. While surface charge density cannot be directly controlled in electrochemical experiments, it can be estimated from the potential of zero charge and the differential double layer capacitance curve. In this mini-review, taking the metal/aqueous solution interface as the study case, we summarize the recent advances in determining their potential of zero charge and Helmholtz capacitance with ab initio molecular dynamics simulations. By comparing computational and theoretical results, we also discuss factors that influence the potential of zero charge and Helmholtz capacitance, including metal surface work function, metal-solvent chemical interactions, electrode polarization, and ion hydration structure at the interface. These insights provide a more detailed microscopic understanding of the electric double layer.