Site-Blocking Strategy Boosts H2S Tolerance in Platinum-Based Hydrogen Oxidation Catalysts
Wei Kang1, Tao Shen1, Ying Wang2
1College of Energy, College of Chemistry and Chemical Engineering, College of Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Xiamen University, Xiamen, 361005, China.
Angewandte Chemie (International Ed. in English)
|July 3, 2025
Summary
Platinum-ruthenium alloy catalysts resist hydrogen sulfide poisoning in proton exchange membrane fuel cells. This study reveals how ruthenium modifies platinum
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- Proton exchange membrane fuel cells (PEMFCs) are promising for energy conversion.
- Platinum catalysts for hydrogen oxidation reaction (HOR) are susceptible to irreversible poisoning by hydrogen sulfide (H2S).
- The exact mechanisms of H2S poisoning on PEMFC catalysts remain unclear.
Purpose of the Study:
- To elucidate the mechanism of H2S poisoning on platinum (Pt) and platinum-ruthenium (PtRu) alloy catalysts.
- To investigate the role of ruthenium in mitigating H2S poisoning.
- To develop improved, poison-resistant catalysts for PEMFCs.
Main Methods:
- In situ Raman spectroscopy to identify adsorbed species.
- Theoretical calculations to understand electronic interactions.
- Comparative performance testing of Pt and PtRu catalysts under H2S exposure.
Main Results:
- On pure Pt, H2S dissociates into S* and HS* intermediates that poison active sites.
- On PtRu alloys, sulfur species were not detected on Pt sites, and OH species appeared on Ru sites.
- Ruthenium alloying weakens sulfur adsorption on Pt through electronic effects and site blocking.
Conclusions:
- Ruthenium in PtRu alloys enhances poison resistance by altering active site geometry and electronic properties.
- Developed PtRu/C catalysts show significantly improved stability against H2S poisoning compared to commercial Pt/C.
- This research provides fundamental insights for designing robust, H2S-resistant fuel cell catalysts.
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