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

Area of Science:

• Surface Science
• Computational Chemistry
• Electrochemistry

Background:

• The potential of zero charge (PZC) is crucial for understanding metal-water interfaces.
• The Volta potential difference (ΔΦ) quantifies the difference between PZC and the metal's work function (Φ_M).
• Accurate determination of PZC and ΔΦ is essential for predicting interfacial behavior.

Purpose of the Study:

• To model and investigate the relationship between Volta potential difference (ΔΦ) and water adsorption energy (E_ads) at metal/water interfaces.
• To elucidate the underlying mechanisms governing the correlation between ΔΦ and E_ads.
• To provide a predictive tool for estimating ΔΦ and PZC in metal-water systems.

Main Methods:

• Utilized ab initio molecular dynamics simulations to model 11 distinct metal/water interfaces.
• Analyzed the electronic structure and interfacial potential changes.
• Quantified water adsorption energies (E_ads) on metal surfaces.

Main Results:

• A significant linear correlation was discovered between the Volta potential difference (ΔΦ) and the adsorption energy of water (E_ads).
• Adsorption energy (E_ads) was found to dictate the coverage of chemisorbed water, influencing the electronic potential change (ΔΦ_el).
• The Volta potential difference (ΔΦ) is primarily governed by the electronic component (ΔΦ_el), with minimal contribution from orientational dipoles.

Conclusions:

• The established linear correlation between ΔΦ and E_ads provides a valuable method for estimating interfacial potentials.
• This relationship simplifies the prediction of the potential of zero charge (PZC) and Volta potential difference (ΔΦ) for new metal surfaces.
• The findings offer a pathway for more efficient characterization of metal-water interfaces in various electrochemical applications.