Dynamically Activating Inert Ti⁴⁺ Sites to Redirect the Oxygen Evolution Pathway Toward Practical PEM Water...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing highly active and durable non-iridium electrocatalysts is critical for scalable proton exchange membrane water electrolyzers (PEMWE).
• The oxygen evolution reaction (OER) is a key process in water electrolysis, but often requires expensive iridium-based catalysts.
• Existing catalysts face challenges in activity, durability, and cost-effectiveness for widespread PEMWE application.

Purpose of the Study:

• To develop a highly active and durable non-iridium electrocatalyst for the acidic oxygen evolution reaction (OER).
• To investigate a novel acid-dissolution inverse-doping strategy for synthesizing uniform Ti-doped RuO2 (Ti-RuO2).
• To understand the mechanism behind the enhanced activity and stability of the Ti-RuO2 catalyst.

Main Methods:

• Synthesis of Ti-doped RuO2 (Ti-RuO2) using an acid-dissolution inverse-doping strategy.
• Characterization using operando spectroscopy and theoretical calculations.
• Performance testing in acidic OER conditions and a practical proton exchange membrane water electrolyzer (PEMWE) device.

Main Results:

• Ti-RuO2 exhibits atomic-level uniformity, inducing compressive lattice strain and unique orbital hybridization.
• The catalyst achieves an overpotential of 218 mV at 10 mA cm-2 and stable operation for over 800 h.
• In a PEMWE device, Ti-RuO2 delivers 3 A cm-2 at 1.787 V, exceeding US DOE 2026 targets, with over 400 h stability at 1 A cm-2.

Conclusions:

• The developed Ti-RuO2 catalyst offers a promising non-iridium alternative for efficient and stable OER in PEMWE.
• The acid-dissolution inverse-doping strategy provides a general approach for dynamic dopant activation in catalysts.
• This work advances the development of cost-effective and high-performance electrocatalysts for clean hydrogen production.