Static and dynamic water structures at interfaces: A case study with focus on Pt(111).

Area of Science:

• Computational chemistry
• Materials science
• Surface science

Background:

• Accurate atomistic simulations of aqueous solid-liquid interfaces require explicit water description, ideally via ab initio molecular dynamics.
• Current applications often use static interfacial water models, focusing on single structures for calculating reaction barriers, which may introduce biases.

Purpose of the Study:

• To systematically investigate the relationship between static and dynamic interfacial water models derived from density functional theory.
• To develop and apply a general protocol for constructing static 2D water layers on surfaces, specifically for the water-Pt(111) interface.

Main Methods:

• Development of a general protocol for creating static 2D water layers on various substrates.
• Application of the protocol to low-index platinum surfaces.
• Comparison of generated static structures with dynamic ensembles using the Smooth Overlap of Atomic Positions descriptor.

Main Results:

• Identified structural overlap between static and dynamic water models, but static models tend to overemphasize in-plane hydrogen bonding.
• The low-temperature hexagonal ice-like structure particularly exaggerates in-plane hydrogen bonding.
• Observed a complex interplay between water structure, work function, and adsorption energy on the Pt(111) surface.

Conclusions:

• Reliance on single, static water models can introduce systematic biases in interface simulations.
• Averaging over consistently created structural ensembles, as proposed, can mitigate these biases.
• The study provides a framework for more robust atomistic treatments of aqueous interfaces.