Making a giant leap in the ‘tiny’ field of nanoscience, a multi-institutional team of researchers is the first to create nanoscale particles composed of up to eight distinct elements generally known to be immiscible, or incapable of being mixed or blended together. The blending of multiple, unmixable elements into a unified, homogenous nanostructure, called a high entropy alloy nanoparticle, greatly expands the landscape of nanomaterials—and what we can do with them.
This research makes a significant advance on previous efforts that have typically produced nanoparticles limited to only three different elements and to structures that do not mix evenly. Essentially, it is extremely difficult to squeeze and blend different elements into individual particles at the nanoscale. The leading research team, which includes engineers at the University of Maryland, College Park (UMD), published a peer-reviewed paper based on the research featured on the March 30 cover of Science.
“Imagine the elements that combine to make nanoparticles as Lego building blocks. If you have only one to three colors and sizes, then you are limited by what combinations you can use and what structures you can assemble,” explains Liangbing Hu, associate professor of materials science and engineering at UMD and one of the corresponding authors of the paper. “What our team has done is essentially enlarged the toy chest in nanoparticle synthesis; now, we are able to build nanomaterials with nearly all metallic and semiconductor elements.”
The researchers say this advance in nanoscience opens vast opportunities for a wide range of applications that includes catalysis (the acceleration of a chemical reaction by a catalyst), energy storage (batteries or supercapacitors), and bio/plasmonic imaging, among others.
To create the high entropy alloy nanoparticles, the researchers employed a two-step method of flash heating followed by flash cooling. Metallic elements such as platinum, nickel, iron, cobalt, gold, copper, and others were exposed to a rapid thermal shock of approximately 3,000 degrees Fahrenheit, or about half the temperature of the sun, for 0.055 seconds. The extremely high temperature resulted in uniform mixtures of the multiple elements. The subsequent rapid cooling (more than 100,000 degrees Fahrenheit per second) stabilized the newly mixed elements into the uniform nanomaterial.
“Our method is simple, but one that nobody else has applied to the creation of nanoparticles. By using a physical science approach, rather than a traditional chemistry approach, we have achieved something unprecedented,” says Yonggang Yao, a Ph.D. student at UMD and one of the lead authors of the paper.
To demonstrate one potential use of the nanoparticles, the research team used them as advanced catalysts for ammonia oxidation, which is a key step in the production of nitric acid (a liquid acid that is used in the production of ammonium nitrate for fertilizers, making plastics, and in the manufacturing of dyes). They were able to achieve 100 percent oxidation of ammonia and 99 percent selectivity toward desired products with the high entropy alloy nanoparticles, proving their ability as highly efficient catalysts.
Yao says another potential use of the nanoparticles as catalysts could be the generation of chemicals or fuels from carbon dioxide.
“The potential applications for high entropy alloy nanoparticles are not limited to the field of catalysis. With cross-discipline curiosity, the demonstrated applications of these particles will become even more widespread,” says Steven D. Lacey, a Ph.D. student at UMD and also one of the lead authors of the paper.
This research was performed through a multi-institutional collaboration of Prof. Liangbing Hu’s group at the University of Maryland, College Park; Prof. Reza Shahbazian-Yassar’s group at University of Illinois at Chicago; Prof. Ju Li’s group at the Massachusetts Institute of Technology; Prof. Chao Wang’s group at Johns Hopkins University; and Prof. Michael Zachariah’s group at the University of Maryland, College Park.
What outside experts are saying about this research:
“This is quite amazing; Dr. Hu creatively came up with this powerful technique, carbo-thermal shock synthesis, to produce high entropy alloys of up to eight different elements in a single nanoparticle. This is indeed unthinkable for bulk materials synthesis. This is yet another beautiful example of nanoscience!,” says Peidong Yang, the S.K. and Angela Chan Distinguished Professor of Energy and professor of chemistry at the University of California, Berkeley and member of the American Academy of Arts and Sciences.
“This discovery opens many new directions. There are simulation opportunities to understand the electronic structure of the various compositions and phases that are important for the next generation of catalyst design. Also, finding correlations among synthesis routes, composition, and phase structure and performance enables a paradigm shift toward guided synthesis,” says George Crabtree, Argonne Distinguished Fellow and director of the Joint Center for Energy Storage Research at Argonne National Laboratory.
More from the research coauthors:
“Understanding the atomic order and crystalline structure in these multi-element nanoparticles reveals how the synthesis can be tuned to optimize their performance. It would be quite interesting to further explore the underlying atomistic mechanisms of the nucleation and growth of high entropy alloy nanoparticle,” says Reza Shahbazian-Yassar, associate professor at the University of Illinois at Chicago and a corresponding author of the paper.
“Carbon metabolism drives ‘living’ metal catalysts that frequently move around, split, or merge, resulting in a nanoparticle size distribution that’s far from the ordinary, and highly tunable,” says Ju Li, professor at the Massachusetts Institute of Technology and a corresponding author of the paper.
“This method enables new combinations of metals that do not exist in nature and do not otherwise go together. It enables robust tuning of the composition of catalytic materials to optimize the activity, selectivity, and stability, and the application will be very broad in energy conversions and chemical transformations,” says Chao Wang, assistant professor of chemical and biomolecular engineering at Johns Hopkins University and one of the study’s authors.
The Latest on: High entropy alloy nanoparticles
via Google News
The Latest on: High entropy alloy nanoparticles
- Noble metal-free catalyst system as active as platinum on October 24, 2018 at 6:44 am
Generating alloy nanoparticle libraries Searching for ... they identified a system made of up five elements in which the high entropy effect results in catalytic activity for an oxygen reduction ... […]
- A high-entropy alloy with hierarchical nanoprecipitates and ultrahigh strength on October 12, 2018 at 11:13 am
1 Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong 510640, China. 2 Department of Materials Science and Engineering, Univ... […]
- Researchers present new strategy for extending ductility in a single-phase alloy on June 29, 2018 at 8:47 am
They demonstrated the behavior of such an HGS using the face-centered-cubic CrCoNi medium-entropy alloy (MEA) as a model system. Back stress hardening is usually not obvious in single-phase homogeneou... […]
- Global High Performance Alloys Industry on June 11, 2018 at 11:33 am
LONDON, June 11, 2018 /PRNewswire/ -- This report analyzes the worldwide markets for High Performance Alloys in Metric Tons by the following Alloying Metal and End-use Applications: Alloying Metal - N... […]
- Global High Performance Alloys Markets, 2016-2018 & 2024: Market Trends, Issues & Growth Drivers on May 21, 2018 at 3:51 am
The "High Performance Alloys - Global Strategic Business Report" report has been added to ResearchAndMarkets.com's offering. The report provides separate comprehensive analytics for the US, Canada, Ja... […]
- Ames Lab takes the guesswork out of discovering new high-entropy alloys on May 1, 2018 at 9:33 am
Given the sheer number of possible alloy composition combinations, it would be difficult for experimentalists to know where to look for the next new high-entropy alloy. Not only that, high-entropy all... […]
- With new technique, researchers create metallic alloy nanoparticles with unprecedented chemical capabilities on April 4, 2018 at 8:34 am
The new materials, known as high-entropy-alloy nanoparticles, have created unprecedented catalytic mechanisms and reaction pathways and are expected to improve energy efficiency in the manufacturing p... […]
- Manufacturing Bits: April 3 on April 2, 2018 at 5:00 pm
This homogenous nanostructure is called a high entropy alloy nanoparticle. The ability to devise these types of particles could one day enable new catalysts, energy storage systems and other applicati... […]
- Mashing up metals with carbothermal shock on March 29, 2018 at 10:53 am
On page 1489 of this issue, Yao et al. (5) present an innovative and general route to high-entropy alloys that can mix up to eight elements into single-phase, size-controlled nanoparticles (NPs). High ... […]
via Bing News