Reversible temperature-induced shape transition of Pt nanoparticles supported on Al2O3
Ricardo Pool Mazun1, Salman A Khan2,3, Vinson Liao2
1Department of Chemical Engineering, Virginia Polytechnic Institute and State University Blacksburg Virginia 24060 USA.
Nanoscale Advances
|November 19, 2025
Summary
Supported platinum (Pt) nanoparticles reversibly change shape with temperature, impacting their electronic properties and reactivity in hydrogenation. This fluxional behavior is crucial for catalyst design.
Area of Science:
- Materials Science
- Catalysis
- Surface Science
Background:
- Supported platinum nanoparticles are vital industrial catalysts for hydrogenation.
- Temperature significantly influences the electronic and geometric properties of platinum nanoparticles, affecting their reactivity.
Purpose of the Study:
- To investigate the effect of hydrogen and temperature on the shape and electronic properties of platinum nanoparticles supported on alumina.
- To understand the fluxional nature of supported platinum nanoparticles driven by temperature changes.
Main Methods:
- Utilized in situ X-ray absorption spectroscopy and environmental transmission electron microscopy.
- Employed machine learning potentials with force-bias Monte Carlo simulations to model platinum cluster structures.
Main Results:
- Observed reversible shape transformation of platinum nanoparticles from 3D hemispheres to 2-2.5D rafts with increasing temperature (35-400 °C).
- Demonstrated that higher temperatures lead to Pt-Pt bond contraction and increased electron density on Pt, primarily due to shape changes and alumina interaction.
Conclusions:
- Supported platinum nanoparticles exhibit temperature-dependent fluxional behavior, altering their morphology and electronic structure.
- The findings provide insights into the dynamic nature of supported catalysts and their performance optimization.
