Proton Wires via One-Dimensional Water Chains Adsorbed on Metallic Steps

Area of Science:

• Surface science
• Physical chemistry
• Condensed matter physics

Background:

• Proton transfer is fundamental in chemical and biological systems.
• Water chains on metal surfaces present unique reaction pathways.
• Understanding substrate effects is crucial for catalysis and nanotechnology.

Purpose of the Study:

• To investigate proton transfer mechanisms in one-dimensional water chains on metallic steps.
• To elucidate the role of the metal substrate in dictating proton transfer pathways.
• To analyze the influence of hydronium and hydroxyl ions on water chain dynamics.

Main Methods:

• Theoretical analysis of proton transfer processes.
• Computational modeling of water chains on different metal substrates (Ag, Au, Pd, Pt).
• Investigation of reaction mechanisms, including Grotthuss mechanism and charge transfer.

Main Results:

• Two distinct proton transfer mechanisms were identified based on the metal substrate.
• On coinage metals (Ag, Au), spontaneous Grotthuss mechanism dominates.
• On reactive metals (Pd, Pt), proton adsorption and subsequent charge transfer along the water wire occur with low activation barriers.

Conclusions:

• The metal substrate significantly influences proton transfer dynamics in adsorbed water chains.
• Reactive metal surfaces enable efficient charge transport through unbalanced hydroxyl ions.
• This study provides insights into substrate-mediated proton transfer relevant to surface chemistry and materials science.