Linear Correlation between Water Adsorption Energies and Volta Potential Differences for Metal/water Interfaces

Abstract

Potential of zero charge (PZC) is an important reference for understanding the interface charge and structure at a given potential, and its difference from the work function of metal surface (ΦM) is defined as the Volta potential difference (ΔΦ). In this work, we model 11 metal/water interfaces with ab initio molecular dynamics. Interestingly, we find ΔΦ is linearly correlated with the adsorption energy of water (Eads) on the metal surface. It is revealed that the size of Eads directly determines the coverage of chemisorbed water on the metal surface and accordingly affects the interface potential change caused by electron redistribution (ΔΦel). Moreover, ΔΦ is dominated by the electronic component ΔΦel with little orientational dipole contributing, which explains the linear correlation between ΔΦ and Eads. Finally, it is expected that this correlation can be helpful for effectively estimating the ΔΦel and PZC of other metal surfaces in the future work.