The charged interface between Pt and water: First principles molecular dynamics simulations

Abstract

The charged interface between a platinum electrode and an aqueous solution is investigated by first-principles molecular dynamics simulations in which charges in the system are controlled by the effective screening medium method under periodic boundary conditions. H3O+ and OH are located above or on the Pt surface. Water molecules rotate to screen the electric field induced by the charge accumulated on the Pt surface. The time-averaged electrostatic potential near the Pt surface is structured with a flattened “bulk” region. The potential difference between the Pt Fermi level and the bulk potential is proportional to the charge and is used to estimate the Pt electrode potential via the PZC (potential of the zero charge). The surface charge significantly polarizes the water molecules near the Pt surface. The OH stretching frequency of molecules on the negatively charged (7 ∼ 14 μC/cm2) Pt electrode shift to lower values (red shift) by 100 ∼ 200 cm−1. For the positively charged Pt lattice, a complex feature results from a charge transfer reaction that takes place there. The electrode structure is also influenced by accumulated charge as the distance between the top surface Pt layer and the next layer underneath increases for both the negatively and positively charged surfaces.

The electric double layer at metal-water interfaces revisited based on a charge polarization scheme

“…As the computer power increases, electrochemical systems are becoming accessible to first principles simulations [25,[27][28][29]. For example, AIMD simulations have already been performed yielding values of the pzc close to experimental values [28,29].…”

Advances and challenges for experiment and theory for multi-electron multi-proton transfer at electrified solid–liquid interfaces

“…[358][359][360][361][362][363] To avoid duplication, here we just summarize recent application of our method. The ab initio molecular dynamics (AIMD) simulation was combined with ESM model to the problem of oxygen reduction reaction or water splitting on Pt, 277,[364][365][366] hydrogen evolution on Ag, 367 and an ionic liquid on Li. 368 The constant chemical potential scheme was applied to the problem of redox level, 369 Pt electrode, 110 and oxygen evolution reaction pathways.…”

Force-based method to determine the potential dependence in electrochemical barriers

“…11,12,14 In the past decade, a variety of methods to address this challenge have been developed. 11,12,[14][15][16][17][18][19][20][21][22][23][24][25] These methods can be broadly grouped into two categories, extrapolation and grand-canonical schemes. Extrapolation methods seek to determine activation energies at the limit of infinite cell size by correcting DFT energies for finite cell size effects.…”