Direct visualization of hydrogen absorption dynamics in individual palladium nanoparticles
Tarun C Narayan1, Fariah Hayee2, Andrea Baldi1,3
1Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305, USA.
Nature Communications
|January 17, 2017
Summary
Palladium nanocube transformations during hydrogenation reveal unique durability. Nanoparticles self-repair crystallographic imperfections, unlike bulk materials, enhancing their stability for energy storage applications.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Energy storage materials often face degradation due to volume changes during operation.
- Nanomaterials exhibit enhanced durability compared to bulk counterparts, but the underlying mechanisms require detailed investigation.
Purpose of the Study:
- To investigate the real-time mechanism of hydrogenation in single-crystalline palladium nanocubes.
- To understand the structural evolution and defect dynamics during phase transformation in palladium nanoparticles.
Main Methods:
- In situ environmental scanning transmission electron microscopy (STEM) with 3 nm resolution to observe hydrogen absorption.
- Dark-field imaging with 1 nm resolution to analyze reaction intermediates and structural changes.
Main Results:
- Hydrogenation initiates via nucleation and growth at the corners of palladium nanocubes.
- Phase propagation leads to lattice misorientation (1.5%) and temporary crystal quality reduction.
- Palladium nanoparticles recover to a pristine state after complete transformation, eliminating defects.
Conclusions:
- The unique ability of palladium nanoparticles to accommodate and eliminate crystallographic imperfections contributes to their superior durability over bulk materials.
- Understanding these nanoscale transformation mechanisms is crucial for designing robust energy storage systems.
