4f-modified Ru-O polarity as a descriptor for efficient electrocatalytic acidic oxygen evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton exchange membrane water electrolysis (PEMWE) requires efficient non-iridium oxygen evolution reaction (OER) catalysts.
• Current catalysts face challenges with sluggish kinetics and dissolution, hindering hydrogen production.

Purpose of the Study:

• To develop novel 4f-orbital-modified RuO2 (4f-RuO2) nanocatalysts with tunable Ru-O polarity for improved OER performance.
• To investigate the relationship between Ru-O bond polarity and OER activity and stability.

Main Methods:

• Synthesis of 4f-RuO2 nanocatalysts using a 4f-induced covalent polarity modulation strategy.
• Electrochemical characterization of OER activity and stability in acidic media.
• In situ synchrotron infrared and X-ray absorption spectroscopy, alongside theoretical calculations.

Main Results:

• OER activity of 4f-RuO2 demonstrated a volcano-shaped dependence on Ru-O bond polarity.
• The optimal 4f-Nd-RuO2 catalyst achieved an ultra-low overpotential (214 mV at 10 mA cm-2) and robust stability.
• Modulation of Ru-O polarity via f-p-d orbital coupling was shown to enhance intermediate adsorption and prevent Ru over-oxidation.

Conclusions:

• 4f-orbital modification is an effective strategy to tune Ru-O polarity and enhance OER performance.
• The valence f-p-d gradient orbital coupling mechanism explains the improved activity and durability.
• This approach provides a descriptor for designing advanced acidic OER catalysts.