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Updated: Jan 30, 2026
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Published on: July 24, 2021
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Revealing the atomic ordering of binary intermetallics using in situ heating techniques at multilength scales
Yin Xiong1, Yao Yang1, Howie Joress2,3
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853.
Summary
Ordered intermetallic nanoparticles, like platinum-cobalt (Pt3Co), show enhanced fuel cell performance. Optimizing annealing improves their ordered structure, boosting activity and durability for the oxygen-reduction reaction (ORR).
Area of Science:
- Materials Science
- Electrochemistry
- Nanotechnology
Background:
- Ordered intermetallic nanoparticles are crucial electrocatalysts for oxygen-reduction reaction (ORR) in proton-exchange membrane fuel cells (PEMFCs).
- Conventional characterization methods like powder X-ray diffraction (PXRD) may misidentify catalyst phases after annealing, potentially indicating mixed ordered and disordered structures.
Purpose of the Study:
- To quantitatively investigate the impact of annealing conditions on the ordering of platinum-cobalt (Pt3Co) nanoparticles using in situ synchrotron X-ray diffraction.
- To determine the order-disorder phase transition (ODPT) temperature of Pt3Co nanoparticles and compare it to bulk materials.
- To visualize atomic-scale morphological changes and ordering using in situ electron microscopy.
Main Methods:
- In situ heating synchrotron X-ray diffraction to analyze nanoparticle ordering under various annealing conditions.
- Monte Carlo simulations to predict the ODPT temperature of Pt3Co nanoparticles.
- In situ heating electron microscopy for atomic-scale visualization of nanoparticle structure and morphology.
- Membrane electrode assembly (MEA) testing to evaluate electrocatalyst performance.
Main Results:
- Pt3Co nanoparticles exhibit a lower ODPT temperature compared to their bulk counterparts.
- Higher degrees of ordering in Pt3Co nanoparticles correlate with increased electrocatalytic activity and durability.
- Optimally annealed Pt3Co/C nanoparticles demonstrated significantly enhanced durability in MEA tests compared to disordered catalysts.
Conclusions:
- The annealing process critically influences the degree of ordering in intermetallic nanoparticles.
- Understanding and controlling annealing conditions are essential for maximizing the electrocatalytic performance of ordered intermetallic catalysts.
- Optimized ordering in Pt3Co nanoparticles leads to superior durability in PEMFC applications.
Keywords:
in situ heating TEMin situ heating XRDordered intermetallicsorder–disorder phase transitionoxygen reduction reactionMore Related Videos
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