Stable Hexagonal Close-Packed CoRu/C Nanocrystals for Highly Efficient Hydrogen Oxidation Electrocatalysis

Area of Science:

• Electrochemistry
• Materials Science
• Nanotechnology

Background:

• The hydrogen oxidation reaction (HOR) is crucial for anion exchange membrane fuel cells (AEMFCs) but faces challenges with slow kinetics and CO poisoning.
• Crystallographic phase engineering of cobalt-based nanomaterials for HOR catalysis is an underexplored area.

Purpose of the Study:

• To investigate the effect of crystallographic phase (hcp vs. fcc) on the HOR activity of CoRu nanocrystals.
• To develop advanced electrocatalysts for improved AEMFC performance.

Main Methods:

• Synthesis of hexagonal close-packed (hcp) and face-centered cubic (fcc) CoRu nanocrystals anchored on carbon nanosheets.
• Electrochemical characterization of HOR activity, durability, and CO tolerance.
• Density functional theory (DFT) calculations to understand reaction mechanisms.

Main Results:

• Hcp CoRu/C catalysts demonstrated superior alkaline HOR performance compared to fcc CoRu/C, Pt/C, and Ru/C.
• The hcp catalyst achieved significantly higher mass activity and excellent durability over 20,000 seconds.
• DFT revealed that the hcp phase optimizes hydrogen binding and hydroxyl adsorption, enhancing HOR kinetics and CO tolerance.

Conclusions:

• Crystallographic phase engineering of CoRu is an effective strategy to enhance HOR electrocatalysis in alkaline media.
• This approach offers a promising alternative to traditional composition-based catalyst design for AEMFCs.