Platinum/Cation Interactions in Alkaline Media Observed by Constant Potential Molecular Dynamics

The influence of cations on the properties of a chemisorbed species-free Pt(100)/1 M (X)-OH (X = Na, K, Cs) interface is explored using the MetalWalls software. Specifically, tools are developed to gather observations on (i) the distribution of charges within the electrode, (ii) the distribution of cations and anions within the electrochemical double layer, and (iii) the water mobility and orientation. They are discussed as a function of the nature of the cation and the magnitude of the potential. Differences are observed in the individual charges taken by interfacial platinum atoms that translate into drastically modified charge profiles as a function of the nature of the cation. These are intertwined with the distribution of the cations and anions (i.e., OH^-) at a distance <1 nm from the electrode. Not only said distribution is influenced, but also the solvation of cations, and the mobility and orientation of water molecules. Ultimately, this work (i) presents a new application of the MetalWalls software for technologies that are of great relevance nowadays and (ii) discusses from a computational standpoint the layered influence of the nature of the cation onto properties of the Pt(100)/electrolyte interface in alkaline media.