Molecular dynamics simulations of the electrical double layer at 1 M potassium halide solution/Hg electrode interfaces

Abstract

This work presents the results from molecular dynamics simulations (MDS) of the electrical double layer (EDL) at mercury/1 M KF, KCl, KBr and KI solutions interfaces at an uncharged metal phase. The model assumes a solid structure of the mercury phase and a hard geometry of the water molecules. Ab initio potentials between all components of the system were used. The values obtained for the potential drop were compared with the shifts of the zero charge potential (ZCP) found experimentally for the corresponding systems. A comparison was drawn between the behaviour of the ions close to the phase boundary with MDS obtained by other authors. A certain discrepancy was observed between the potential differences established in this work and the ZCP obtained by direct electrochemical measurements. The analysis made gives grounds to conclude that taking into account the liquid structure of mercury in the MDS of the EDL is an important condition for obtaining results comparable with experiment.