Atomic-Scale Characterization of Interfacial Water on LaTiO₂N(100) Surface

Area of Science:

• Materials Science
• Surface Chemistry
• Photocatalysis

Background:

• Perovskite oxynitride LaTiO2N is a promising material for visible-light-driven photocatalytic water splitting.
• Understanding surface dynamics at the catalyst-water interface is crucial for optimizing performance.
• The behavior of LaTiO2N(100) surface in aqueous environments is not well understood.

Purpose of the Study:

• To investigate the water arrangement and adsorption on the LaTiO2N(100) surface.
• To elucidate the role of explicit solvent effects and surface dynamics.
• To explore the implications for photocatalytic water splitting and oxygen evolution reactions.

Main Methods:

• State-of-the-art density functional theory molecular dynamics (DFT-MD) simulations.
• Electrochemical measurements.
• Analysis of explicit solvent effects and surface configurations.

Main Results:

• The LaTiO2N(100) surface displays significant hydrophilic character.
• Spontaneous water dissociation occurs at undercoordinated Ti sites, forming stabilizing hydroxyl groups.
• Thermodynamically stable surface terminations were identified, promoting hydrogen-bond networks for proton-coupled electron transfer.
• Surface Pourbaix diagrams indicate hydroxylated configurations under various electrochemical conditions.

Conclusions:

• Explicitly treating solvent environments and their dynamics is critical for accurate modeling of LaTiO2N.
• Surface hydroxylation plays a key role in stabilizing the catalyst and potentially enhancing oxygen evolution reaction (OER) activity.
• These findings provide a foundation for designing improved perovskite oxynitride catalysts for sustainable water splitting.