Multigrain Ruthenium Nanocrystals with Enriched (10 1 ¯ ${{\bar{1}}}$ 1) Facets for Enhanced Hydrogen Oxidation in...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Ruthenium (Ru) materials are explored as cost-effective alternatives to platinum for the hydrogen oxidation reaction (HOR) in anion exchange membrane fuel cells (AEMFCs).
• A key challenge for Ru-based catalysts is their limited stability in alkaline electrolytes due to strong oxophilicity.

Purpose of the Study:

• To develop an oxidation-resistant Ru multigrain catalyst with exposed (10\bar{1}1) facets for enhanced HOR catalysis in AEMFCs.
• To investigate the catalytic performance and stability of the novel Ru catalyst in alkaline media.

Main Methods:

• Synthesis of a Ru multigrain catalyst with controlled facet exposure.
• Electrochemical characterization including kinetic current density and stability window measurements.
• Fabrication and testing of an anion exchange membrane fuel cell (AEMFC) using the developed catalyst.

Main Results:

• The Ru catalyst exhibited a high kinetic current density of 61 mA cm⁻² at 50 mV overpotential, significantly outperforming commercial Ru- and Pt-based catalysts.
• The catalyst demonstrated excellent stability up to 0.3 V vs. RHE and enhanced tolerance to CO poisoning.
• AEMFCs utilizing this catalyst achieved peak power densities of 1.31 W cm⁻² (H₂-O₂) and 1.06 W cm⁻² (H₂-air) at 90 °C, with steady operation.

Conclusions:

• The (10\bar{1}1) facets of the Ru catalyst possess superior oxidation and hydrogen oxidation barriers compared to (0002) facets, leading to exceptional HOR activity and stability.
• This oxidation-resistant Ru multigrain catalyst represents a promising advancement for high-performance and durable AEMFCs.