Tracking Water Dissociation on RuO₂(110) Using Atomic Force Microscopy and First-Principles Simulations.

Area of Science:

• Electrochemistry
• Surface Science
• Materials Science

Background:

• The oxygen evolution reaction (OER) is critical for energy conversion technologies.
• Interfacial water interaction with transition metal oxides is key to OER.
• Ruthenium dioxide (RuO2) is a well-established OER electrocatalyst.

Purpose of the Study:

• To visualize and understand water dissociation on RuO2(110) during OER.
• To investigate the role of interfacial water activation in OER.
• To map the surface phase diagram and interpret cyclic voltammetry of RuO2(110).

Main Methods:

• Atomic force microscopy (AFM) to image water dissociation.
• First-principles calculations incorporating interfacial polarization, capacitive charging, and adsorbate interactions.
• Surface phase diagram mapping and cyclic voltammetry interpretation.

Main Results:

• Direct visualization of surface water dissociation into OH* and O* on RuO2(110).
• Observed transformation of a one-dimensional water network to a two-dimensional adsorbate pattern with increasing oxidative potential.
• Calculations confirmed cooperative dehydrogenation of adsorbed water and OH* as the driving mechanism.

Conclusions:

• Water activation on RuO2(110) is a collective phenomenon.
• The study provides a quantitative interpretation of OER on RuO2(110) surfaces.
• Visualizing water dissociation offers critical insights into OER mechanisms on conductive oxides.