Understanding ion-transfer reactions in silver electrodissolution and electrodeposition from first-principles...

Area of Science:

• Electrochemistry
• Materials Science
• Computational Chemistry

Background:

• The electrified aqueous/metal interface is vital for energy conversion and storage devices.
• Atomistic understanding of interfacial electrochemical reactions remains a significant challenge for both experimental and computational methods.

Purpose of the Study:

• To investigate ion-transfer reactions in anodic silver (Ag) corrosion/deposition using a combined simulation and experimental approach.
• To develop a validated, atomistic molecular model for interfacial electrochemical processes.

Main Methods:

• Density functional theory (DFT) calculations with explicit electrode potential modeling and a hybrid solvation model.
• Temperature-dependent voltage-step experiments on gold (Au)-supported silver (Ag) nanocluster substrates.
• Analysis of free energy curves, kinetics, partial charge profiles, and reaction trajectories.

Main Results:

• Calculated free energy barriers (0.2 eV) and asymmetries align with experimental activation energies (0.4 eV) and transfer coefficients.
• Identified key factors controlling the reaction barrier: ion solvation, metal-metal bonding, and image charge stabilization.
• Simulations predict defect generation for corrosion initiation via a vacancy-adatom intermediate.

Conclusions:

• The study provides the first validated molecular model for key steps in metal dissolution/deposition reactions.
• This work enhances the understanding of interfacial electrochemical processes relevant to energy sciences.
• The use of Ag nanoclusters effectively isolates ion transfer kinetics from nucleation effects.