Regulating Surface Hydroxyl Groups in CoO_x via Atomically Dispersed Ru for Durable Acidic Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Atomically dispersed catalysts offer high active site utilization but struggle with stability in acidic oxygen evolution reactions (OER).
• Support material activity and acid corrosion resistance are critical limitations for precious metal catalysts in acidic OER.

Purpose of the Study:

• To enhance the durability and performance of catalysts for acidic OER by anchoring ruthenium (Ru) sites onto a cobalt oxide (CoO𝑥) support.
• To investigate the structure-activity relationships and mechanistic insights of Ru/Co3O4 catalysts for improved OER performance.

Main Methods:

• Synthesis of Ru/Co3O4 catalysts via high-temperature treatment (≥450 °C).
• Electrochemical characterization including OER performance testing (overpotential, stability) in acidic media.
• Experimental and theoretical analyses to understand electronic structure modulation and surface species interactions.

Main Results:

• Ru/Co3O4 achieved a low OER overpotential of 280 mV at 50 mA cm⁻² with negligible potential loss over 1000 h.
• Catalyst demonstrated stable operation in a proton exchange membrane water electrolysis device for 450 h at 0.2 A cm⁻² and 200 h at 0.5 A cm⁻².
• High-temperature treatment modulated CoO𝑥 electronic structure, regulating hydroxyl coverage and mitigating surface deactivation.

Conclusions:

• Anchoring Ru sites onto CoO𝑥 significantly enhances catalyst durability for acidic OER.
• The developed Ru/Co3O4 catalyst represents a promising low-noble-metal alternative for efficient and stable water electrolysis.
• Understanding the electronic modulation and surface chemistry is key for designing advanced catalysts.