Oxygen Vacancy-Electron Polarons Featured InSnRuO₂ Oxides: Orderly and Concerted In-Ov-Ru-O-Sn Substructures for...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton exchange membrane water electrolysis (PEMWE) requires efficient and stable electrocatalysts for water oxidation.
• Polymetallic oxides offer tunable electronic and geometric structures for catalytic applications.
• Isomorphic substitution is a strategy to engineer material properties.

Purpose of the Study:

• To fabricate novel InSnRuO2 oxides with controlled oxygen vacancies (Ov) and electron polarons.
• To investigate the catalytic performance of InSnRuO2 for acidic water oxidation and PEMWE.
• To elucidate the structure-activity relationships governing the enhanced electrocatalytic properties.

Main Methods:

• In situ isomorphic substitution using trivalent Indium species to create Ov-free electron polarons.
• Fabrication of well-defined rutile InSnRuO2 oxides.
• Electrochemical testing including overpotential, mass activity measurements, and long-term stability tests in PEMWE.

Main Results:

• InSnRuO2 exhibited an ultralow overpotential of 183 mV and a mass activity of 103.02 A mgRu−1 for water oxidation.
• The catalyst demonstrated stable operation in PEMWE at 1.56 V for 200 hours at 50 mA cm−2, surpassing IrO2||Pt/C.
• Accelerated degradation tests showed no significant voltage increase in pure water electrolytes.
• The performance is attributed to concerted In-Ov-Ru-O-Sn substructures and self-trapped Ov-electron polarons enhancing kinetics and stability.

Conclusions:

• The developed InSnRuO2 oxides with engineered Ov-electron polarons provide highly efficient and stable electrocatalysis for PEMWE.
• The study highlights the potential of polaron-induced ordered substructures for next-generation Ru-based catalysts.
• This work offers a new avenue for designing advanced materials for efficient water splitting.