Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers develop unique method for creating uniform nanoparticles

07.05.2013
University of Illinois researchers have developed a new way to produce highly uniform nanocrystals used for both fundamental and applied nanotechnology projects.
“We have developed a unique approach for the synthesis of highly uniform icosahedral nanoparticles made of platinum (Pt),” explained Hong Yang, a professor of chemical and biomolecular engineering and a faculty affiliate at the Center for Nanoscale Science and Technology at Illinois. “This is important both in fundamental studies—nanoscience and nanotechnology—and in applied sciences such as high performance fuel cell catalysts.

Yang’s research group focuses on the synthesis and understanding structure-property relationship of nanostructured materials for applications in energy, catalysis, and biotechnology. Its paper, "Highly Uniform Platinum Icosahedra Made by the Hot Injection-Assisted GRAILS Method," was published this week in Nano Letters.

“Although polyhedral nanostructures, such as a cube, tetrahedron, octahedron, cuboctahedron, and even icosahedron, have been synthesized for several noble metals, uniform Pt icosahedra do not form readily and are rarely made,” stated Wei Zhou, a visiting scholar with Yang’s research group and the paper’s first author.

An icosahedron crystal is a polyhedron with 20 identical equilateral triangular faces, 30 edges and 12 vertices. According to Yang, icosahedral shaped crystals can improve the catalytic activity in oxygen reduction reaction partly because of the surface strain.
“The key reaction step to improve the activity of oxygen electrode catalysts in the hydrogen fuel cell is to optimize the bond strength between Pt and absorbed oxygen-containing intermediate species,” Yang said. “This allows the rapid production of water and let the intermediate react and leave the surface quickly so the catalyst site can be used again.”

“Unlike many other forms of metal nanoparticles, an icosahedral nanocrystal is not a single crystal, but has many twin (defect) boundaries within this shape. Previous simulation data suggest that it is unstable for Pt nanoparticles to exist in this shape at about >1-2 nm and, indeed, it is uncommon for Pt nanoparticles to have this morphology.”
Highly uniform Pt icosahedral nanocrystals with an edge length of 8.8 nm were synthesized by Yang’s research group.They were made from platinum acetylacetonate in dodecylamine and with small amount of oleic acid using a hot injection-assisted GRAILS (gas reducing agent in liquid solution) approach. In the GRAILS approach, the inclusion of CO gas greatly facilitates the formation of well-defined shapes.

“Our results showed that the key factors for the shape control include fast nucleation, kinetically controlled growth, and protection from oxidation by air,” Zhou added. By adjusting these key parameters, Pt hyper-branched rods, cubes, and octapods were also obtained.

“We are currently studying why this shape is formed in our systems and how we can use this principle to produce other unusual and potentially useful Pt and its alloy nanoparticles,” Yang noted. “The high purity (>95%) of the products provides the ideal model materials for studying the structure/morphology-property relationships. Such mechanistic understanding is valuable for the design of advanced, high performance metal and metal alloy catalysts.”

This work was supported by the National Science Foundation.

Contact: Hong Yang, Department of Chemical and Biomolecular Engineering, 217/244-6730.

Writer: Rick Kubetz, Engineering Communications Office, University of Illinois at Urbana-Champaign, 217/244-7716.

Hong Yang | EurekAlert!
Further information:
http://www.illinois.edu

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>