Radial nanochannel-array carbon enables high-performance intermetallic fuel cell catalysts

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Designing efficient platinum-based intermetallic catalysts for fuel cell oxygen-reduction cathodes requires integrating fine nanoparticles, high structural ordering, substantial platinum content, and mesoporous supports.
• Existing supports often struggle to balance these critical properties, limiting catalyst performance and durability.

Purpose of the Study:

• To develop a novel catalyst support material that enables synergistic integration of key properties for enhanced oxygen reduction reaction (ORR) catalysis.
• To synthesize and characterize a highly ordered PtCo intermetallic catalyst supported on radial nanochannel-array carbon spheres (RNCS).
• To evaluate the electrochemical performance and durability of the PtCo-RNCS catalyst in membrane electrode assemblies under demanding conditions.

Main Methods:

• Synthesis of radial nanochannel-array carbon spheres (RNCS) with optimized mesoporous structures.
• Uniform assembly of platinum-cobalt (PtCo) intermetallic nanoparticles onto the RNCS support.
• High-temperature annealing (>1,000°C) to achieve ordered L1₀-PtCo phases and fine particle dispersion.
• Electrochemical testing of the catalyst in membrane electrode assemblies, including performance evaluation under heavy-duty vehicle conditions and accelerated stress testing.

Main Results:

• The RNCS support facilitated the creation of a PtCo intermetallic catalyst with >80% L1₀ ordering and particle sizes <5 nm, even at 40 wt% Pt content.
• The catalyst exhibited exceptional thermal and electrochemical stability due to the nanoconfinement effect of the RNCS support.
• A compelling current density of 2.12 A cm⁻² at 0.70 V was achieved under heavy-duty vehicle conditions.
• The catalyst retained 82.5% of its performance after 150,000 voltage cycles, demonstrating remarkable durability.

Conclusions:

• The developed RNCS support effectively integrates essential merits for high-performance platinum-based intermetallic catalysts.
• The PtCo-RNCS catalyst offers a promising solution for efficient and durable oxygen reduction cathodes in fuel cells, particularly for demanding applications.
• This work advances the design principles for next-generation fuel cell catalysts through innovative support engineering.