Study Reveals How the Formation of Nanoscale Crystal Structures are Controlled

In a first-of-its-kind study, researchers used an ingenious experimental setup and high-energy X-ray beams to observe a high-temperature, high-pressure chemical reaction to establish how the formation of two varied nanoscale crystalline structures in the metal cobalt is controlled.

The method enabled continuous analysis of cobalt nanoparticles as they formed from clusters that include tens of atoms to large crystals measuring 5 nm.

The study offers the proof-of-principle for a novel method to analyze the real-time formation of crystals, with prospective applications for other materials, such as oxides and alloys. The study data created “nanometric phase diagrams” that revealed the conditions controlling the structure of cobalt nanocrystals as they grew.
Published in the Journal of the American Chemical Society on November 13th, 2018, the study applied the U.S. Department of Energy-supported synchrotron X-ray beam lines at Argonne National Laboratory and Brookhaven National Laboratory. It was sponsored by the National Science Foundation.

Crystal formation in bulk cobalt prefers the hexagonal close-pack, or HCP, structure since it reduces energy to produce a stable structure. However, at the nanoscale, cobalt also tends to form the face-centered cubic, or FCC, phase, which possesses a higher energy. That can be stable because the total crystalline energy is affected by the high surface energy of tiny nanoclusters, Chen informed.
“When the clusters are small, we have more tuning effects, which is controlled by the surface energy of the OH minus group or other ligands,” he added. “We can tune the concentration of the OH minus group in the solution so we can tune the surface energy and therefore the overall energy of the cluster.”
In association with scientists from the Department of Materials Science at the University of Maryland and the two national laboratories, Chen and Xuetian Ma, a graduate research assistant, studied the polymorphic structures using experimental, theoretical, and computational modeling methods.


Image Credit:    Allison Carter, Georgia Tech

News This Week

Gene Therapy Promotes Nerve Regeneration

Researchers from the Netherlands Institute for Neuroscience (NIN) and the Leiden University Medical Center (LUMC) have shown that treatment using gene therapy leads to a faster recovery after nerve damage. By combining a surgical [...]

Can man ever build a mind?

The idea that we might create machines more intelligent than ourselves is not new. Myths and folk stories abound with creations such as the bronze automaton Talos, who patrolled the island of Crete in [...]

Cold atoms offer a glimpse of flat physics

These days, movies and video games render increasingly realistic 3-D images on 2-D screens, giving viewers the illusion of gazing into another world. For many physicists, though, keeping things flat is far more interesting. [...]

Viruses as Controllable Nanodevices

Viruses are Nature’s delivery vehicles. Millions of years of evolution have molded them into remarkable machines capable of performing a monumental task vital to their survival: the delivery of genetic material into other organisms. [...]

Updated – NanoApps Medical Inc. Near-Term Projects

NanoApps Medical is investigating the possibility that superparamagnetic nanoparticles (SPIONs) (Figure 1) and other classes of nanoparticles (e.g., gold coated nanoshells) (Figure 2) might have the capacity to target cancerous tumors, metastasizing cancer cells, [...]


Leave A Comment