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
A pea-sized device used to seal tiny but potentially deadly holes in the hearts of premature infants has been approved by U.S. regulators, making it one of the smallest complex medical devices ever invented [...]
Scientists have discovered that squamous cell skin cancers do not require increased glucose to power their development and growth, contrary to a long-held belief about cancer metabolism. The findings could bring about a better [...]
Nanotechnology may well be one of the most talked about industries of the last few years. Predicted to value US$173.95 billion globally by 2025, this fast-moving sector is already delivering major sustainability, health and [...]
Catalysts are chemical matchmakers: They bring other chemicals close together, increasing the chance that they’ll react with each other and produce something people want, like fuel or fertilizer. Since some of the best catalyst [...]
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 [...]
When people are in the early stages of an undiagnosed disease, immediate tests that lead to treatment are the best first steps. But a blood draw—usually performed by a medical professional armed with an [...]
A team of neuroscientists and engineers has developed a tiny, implantable device that has potential to help people with bladder problems bypass the need for medication or electronic stimulators. The team -- from Washington [...]
Nanomedical Device and Systems Design: Challenges, Possibilities, Visions now available to rent on Kindle
To accommodate students who wish to read the book at an affordable cost, Nanomedical Device and Systems Design: Challenges, Possibilities, Visions by Frank Boehm (CEO NanoApps Medical Inc.) is available to rent on Kindle. This book benefits [...]
Graphene-based implant overcomes technical limitation to record brain activity at extremely low frequencies
The body of knowledge about the human brain is growing exponentially, but questions big and small remain unanswered. Researchers have been using electrode arrays to record the brain’s electrical activity for decades, mapping activity [...]
Note: This videoblog is in German. It was produced by the Institute of Art & Art Theory of the University of Cologne. Humanity faces epochal challenges in the age of digitization. In particular, [...]
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, [...]