Size-dependent shape distributions of platinum nanoparticles
Ruikang Ding1, Ingrid M Padilla Espinosa2, Dennis Loevlie3
1Department of Mechanical Engineering and Materials Science, University of Pittsburgh Pittsburgh PA 15261 USA tjacobs@pitt.edu.
Nanoscale Advances
|September 22, 2022
Summary
Thermal energy influences nanoparticle shape, with smaller platinum nanoparticles favoring equilibrium shapes. Larger nanoparticles exhibit non-equilibrium shapes due to increased thermal energy, impacting applications.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Nanoparticle shape is influenced by thermodynamics and kinetics.
- Computational studies suggest thermal energy controls nanoparticle shape distribution.
Purpose of the Study:
- To experimentally investigate the effect of thermal energy on nanoparticle shape distribution.
- To determine the relationship between particle size and shape in platinum nanoparticles.
Main Methods:
- Transmission electron microscopy (TEM) for shape characterization.
- Atomistic simulations including molecular dynamics and a bond-cutting model.
- Boltzmann statistics to explain observed trends.
Main Results:
- Small platinum nanoparticles (<2.5 nm) adopt truncated octahedral shapes (equilibrium).
- Larger nanoparticles exhibit increased prevalence of higher-energy facets, forming non-equilibrium shapes like truncated cuboctahedra.
- Shape distribution strongly depends on particle size.
Conclusions:
- Thermal energy drives shape variation in nanoparticle populations.
- Non-equilibrium facets become more common in larger metal nanoparticles.
- Findings have implications for nanoparticle applications in catalysis and solar energy.
