Scientists capture 3D images of nanoparticles, atom by atom, with unprecedented precision

Scientists capture 3D images of nanoparticles, atom by atom, with unprecedented precision

(Nanowerk News) Since their invention in the 1930s, electron microscopes have helped scientists peer into the atomic structure of ordinary materials like steel, and even exotic graphene. But despite these advances, such imaging techniques cannot precisely map out the 3D atomic structure of materials in a liquid solution, such as a catalyst in a hydrogen fuel cell, or the electrolytes in your car’s battery.
Now, researchers at Berkeley Lab, in collaboration with the Institute for Basic Science in South Korea, Monash University in Australia, and UC Berkeley, have developed a technique that produces atomic-scale 3D images of nanoparticles tumbling in liquid between sheets of graphene, the thinnest material possible.
3D images of platinum particles between 2-3 nm in diameter shown rotating in liquid under an electron microscope
3D images of platinum particles between 2-3 nm in diameter shown rotating in liquid under an electron microscope. Each nanoparticle has approximately 600 atoms. White spheres indicate the position of each atom in a nanoparticle. (Image: IBS)
Their findings were reported in the journal Science ("Critical differences in 3D atomic structure of individual ligand-protected nanocrystals in solution").
“This is an exciting result. We can now measure atomic positions in three dimensions down to a precision six times smaller than hydrogen, the smallest atom,” said study co-author Peter Ercius, a staff scientist at Berkeley Lab’s Molecular Foundry.
The technique, called 3D SINGLE (Structure Identification of Nanoparticles by Graphene Liquid cell Electron microscopy), employs one of the world’s most powerful microscopes at Berkeley Lab’s Molecular Foundry. The researchers captured thousands of images of eight platinum nanoparticles “trapped” in liquid between two graphene sheets – called a “graphene window.”
These graphene sheets – each one just an atom thick – are “strong enough to contain tiny pockets of liquid necessary to acquire high-quality images of the nanoparticles’ atomic arrangement,” Ercius explained.
The researchers then adapted computer algorithms originally designed for biological studies to combine many 2D images into atomic-resolution 3D images.
3D atomic structure of platinum nanoparticles
3D atomic structure of platinum nanoparticles. Each nanoparticle has a diameter of 2-3 nm and contains approximately 600 atoms. (Image: IBS)
The achievement, which improves upon a technique first reported in 2015, marks a significant milestone for the researchers. “With 3D SINGLE, we can determine why such small nanoparticles are more efficient catalysts than larger ones in fuel cells and hydrogen vehicles,” Ercius said.
Source: By Theresa Duque, Berkeley Lab
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