Strain-modulated Ru-O Covalency in Ru-Sn Oxide Enabling Efficient and Stable Water Oxidation in Acidic Solution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Ruthenium dioxide (RuO₂) is a key anode catalyst for proton exchange membrane water electrolyzers.
• Its application is limited by poor long-term stability due to lattice oxygen involvement and ruthenium dissolution during the oxygen evolution reaction (OER).

Purpose of the Study:

• To enhance the stability and activity of Ru-based catalysts for OER by engineering the Ru-O bond covalency.
• To develop a robust electrocatalyst for efficient water splitting.

Main Methods:

• Fabrication of a binary Ru-Sn oxide matrix (RuSnO_x) to introduce tensile strain to RuO₆ octahedrons.
• Characterization of the catalyst's structural and electrochemical properties.
• Evaluation of OER activity and long-term stability in acidic media.

Main Results:

• Tensile strain in RuSnO_x weakened the Ru-O bond, suppressing lattice oxygen participation and Ru dissolution.
• The engineered catalyst exhibited optimized intermediate adsorption energies, boosting OER activity.
• RuSnO_x demonstrated excellent OER activity with an overpotential of 184 mV at 10 mA cm^-2 in 0.1 M HClO₄.
• The catalyst maintained a current density of 10 mA cm^-2 for over 150 hours with minimal potential increase.

Conclusions:

• Tailoring Ru-O bond covalency via tensile strain is an effective strategy to improve the stability of Ru-based OER electrocatalysts.
• RuSnO_x shows exceptional performance and durability for water splitting applications.
• This approach offers a promising pathway for developing advanced electrocatalysts for clean energy technologies.