Atomic-level interface engineering enables efficient and durable acidic hydrogen evolution of osmium at large current...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Osmium (Os) is a cost-effective alternative to platinum (Pt) for hydrogen evolution reaction (HER) catalysts.
• Os-based catalysts lack stability in acidic media due to issues like H* over-adsorption and oxidative dissolution.

Purpose of the Study:

• To develop a highly stable and active osmium single-atom catalyst (OsSA) for the hydrogen evolution reaction (HER).
• To investigate the role of a porous cerium dioxide (CeO2) support in enhancing Os catalyst stability and activity.

Main Methods:

• Designed a porous CeO2 support for atomic dispersion of Os.
• Fabricated an osmium single-atom catalyst on CeO2 (OsSA-CeO2).
• Evaluated the electrocatalytic performance and durability of OsSA-CeO2 for HER under acidic conditions.

Main Results:

• Achieved 100% interfacial anchoring of Os atoms on the porous CeO2 support, preventing aggregation.
• The porous CeO2 support created oxygen vacancies, facilitating H2O dissociation and proton supply.
• OsSA-CeO2 exhibited over 500 hours of durability at 100 mA cm-2 without performance decay, surpassing existing Os-based HER catalysts.

Conclusions:

• Porous CeO2 supports enable complete interfacial anchoring of active metal atoms, significantly enhancing catalytic stability.
• Support activation through oxygen vacancies facilitates proton supply and prevents catalyst dissolution, crucial for sustained HER activity.
• This strategy offers a general approach to designing robust single-atom catalysts for various electrochemical reactions.