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!
Hidden talents: Converting heat into electricity with pencil and paper
20.02.2018 | Helmholtz-Zentrum Berlin für Materialien und Energie
Contacting the molecular world through graphene nanoribbons
19.02.2018 | Elhuyar Fundazioa
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
20.02.2018 | Life Sciences
20.02.2018 | Medical Engineering
20.02.2018 | Physics and Astronomy