Ultrasmall Strained RuO₂ as a Highly Efficient Electrocatalyst for Acidic Oxygen Evolution Reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing non-iridium electrocatalysts for the acidic oxygen evolution reaction (OER) is crucial for efficient proton-exchange-membrane water electrolyzers (PEMWEs).
• Ruthenium oxide (RuO2) is a promising OER catalyst but lacks sufficient durability in acidic media.

Purpose of the Study:

• To improve the OER performance and durability of RuO2 electrocatalysts using strain engineering.
• To investigate the effects of tensile strain on RuO2's adsorption properties and structural stability.

Main Methods:

• Density functional theory (DFT) calculations to predict the impact of tensile strain on RuO2.
• Synthesis of tensile-strained RuO2 nanoparticles using a graphene oxide confinement method.
• Electrochemical testing of the catalyst in acidic media for OER performance and durability assessment.
• Integration of the catalyst into a PEMWE device to evaluate water splitting performance.

Main Results:

• DFT calculations confirmed that tensile strain optimizes adsorption and enhances structural stability of RuO2.
• Synthesized tensile-strained RuO2 nanoparticles exhibited a record low overpotential of 136 mV.
• The catalyst demonstrated high durability, operating over 160 hours at 10 mA cm⁻².
• The PEMWE device achieved a high current density of 3.45 A cm⁻² at 1.8 V and stable operation for 120 hours.

Conclusions:

• Strain engineering is an effective strategy to enhance the OER performance and durability of RuO2 electrocatalysts.
• Tensile-strained RuO2 shows significant potential for practical applications in hydrogen production via PEMWEs.