Suppressing Metal Dissolution in Multi-Grained Catalysts Through Intragrain Atomic Ordering for Stable Fuel Cells.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing stable, high-performance catalysts is crucial for fuel cell technology.
• Structural degradation and elemental dissolution limit the long-term operation of current catalysts.

Purpose of the Study:

• To design and synthesize novel multi-grained NiPt nanocatalysts with enhanced stability and catalytic activity.
• To investigate the role of the atomically ordered Ni3Pt5 phase in improving catalyst durability and performance.

Main Methods:

• Ultrasound-assisted synthesis to promote atomic transposition and form the Ni3Pt5 phase within NiPt nanocrystals.
• Characterization of catalyst structure and composition.
• Performance testing in proton exchange membrane fuel cells under light-duty and heavy-duty vehicle conditions.

Main Results:

• Successfully synthesized multi-grained NiPt nanocatalysts featuring an embedded Ni3Pt5 phase.
• Achieved high mass activity (0.94 A mgPt-1) and current density (421 mA cm-2 @ 0.8 V) under light-duty conditions, retaining 78% activity after testing.
• Demonstrated superior durability under heavy-duty conditions, surpassing U.S. Department of Energy targets with minimal Pt utilization loss and power decrease.

Conclusions:

• The atomically ordered Ni3Pt5 phase is critical for stabilizing NiPt nanocrystals, enhancing both catalytic activity and durability.
• Ni3Pt5 embedded nanocatalysts represent a promising advancement for next-generation proton exchange membrane fuel cells.
• This work addresses key challenges in long-term fuel cell operation through rational catalyst design.