Scientists at the U.S. Naval Research Laboratory (NRL) Materials Science and Technology Division have developed a novel one-step process using, for the first time in these types of syntheses, potassium superoxide (KO2) to rapidly form oxide nanoparticles from simple salt solutions in water.
"Typically, the synthesis of oxide nanoparticles involves the slow reaction of a weak oxidizing agent, such as hydrogen peroxide, with dilute solutions of metal salts or complexes in both aqueous and non-aqueous solvent systems," said Dr. Thomas Sutto, NRL research chemist. "The rapid exothermic reaction of potassium superoxide with the salt solutions results in the formation of insoluble oxide or hydroxide nanoparticulates."
This figure illustrates the ease with which grams of many different types of oxide nanoparticles can be prepared in a single step. The first row of sample vials shows the initial salt solutions of the different elements. The second row shows the product after reaction with potassium superoxide (KO2) and the addition of methanol. The bottom row shows the grams of nanoparticles after being purified by centrifugation.
(Photo: U.S. Naval Research Laboratory)
An important advantage of this method is the capability of creating bulk quantities of materials. NRL has demonstrated that large quantities (over 10 grams) of oxide nanoparticles can be prepared in a single step, which is approximately four orders of magnitude higher yield than many other methods. The metal concentrations, usually in the millimolar (mM) amount, need to be low in order to prevent aggregation of the nanoparticles into larger clusters that could significantly limit the amount of material that can be prepared at any one time.
Oxide nanoparticles have been shown to be crucial components in numerous applications to include electronic and magnetic devices, energy storage and generation, and medical applications such as magnetic nanoparticles for use in magnetic resonance imaging (MRI). In all of these applications, particle size is critical to the utility and function of oxide nanoparticles—decreased particles size results in increased surface area, which can significantly improve the performance of the oxide nanoparticle.
In order to demonstrate the broad scale applicability of this new method, oxide or hydroxide nanoparticles have been prepared from representative elements from across the periodic table to rapidly produce nanometer sized oxides or hydroxides. In addition to the elements converted to oxide nanoparticles in the above illustration, it has also been shown that oxide nanoparticles can be prepared from second and third row transition metals, and even semi-metals such as tin, bismuth, thallium and lead.
One exciting aspect of this technique is that it can also be used to produce blends of nanoparticles. This has been demonstrated by preparing more complex materials, such as lithium cobalt oxide—a cathode material for lithium batteries; bismuth manganese oxide—a multiferroic material; and a 90 degrees Kelvin (K) superconducting Yttrium barium copper oxide material. As such, this new synthetic route to oxide nanoparticles also shows great promise for a multitude of other catalytic, electrical, magnetic, or electrochemical processes, from novel cathodes to solution preparation of other types of ceramic materials.
About the U.S. Naval Research Laboratory
The U.S. Naval Research Laboratory is the Navy's full-spectrum corporate laboratory, conducting a broadly based multidisciplinary program of scientific research and advanced technological development. The Laboratory, with a total complement of approximately 2,500 personnel, is located in southwest Washington, D.C., with other major sites at the Stennis Space Center, Miss., and Monterey, Calif. NRL has served the Navy and the nation for over 90 years and continues to meet the complex technological challenges of today's world. For more information, visit the NRL homepage or join the conversation on Twitter, Facebook, and YouTube.
Daniel Parry | Eurek Alert!
New material could lead to erasable and rewriteable optical chips
07.12.2016 | University of Texas at Austin
Porous crystalline materials: TU Graz researcher shows method for controlled growth
07.12.2016 | Technische Universität Graz
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine