Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Modeling the chemical reactions of nanoparticles

28.03.2006


As science enters the world of the very small, researchers will be searching for new ways to study nanoparticles and their properties. For the past several years, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have been experimenting with new methods for preparing nanoparticles on metal supports, with the aim of creating model catalyst systems to better study the special reactivity of nano-sized catalyst particles.



Brookhaven’s Jan Hrbek will review several of the Lab’s results at the 231st national meeting of the American Chemical Society at the Georgia World Congress Center in Atlanta, GA. Hrbek’s talk will be held on Monday, March 27 at 2:40 pm in Room C209.

Catalysis, the acceleration of a chemical reaction, is tremendously important as an industrial process, underlying most of our energy supply (oil-to-fuel conversion, for example) and 80 percent of the products of the chemical industry. There is a substantial need to understand how catalysts work, and learn to design and make better catalysts. The work at Brookhaven is aimed at understanding how the detailed atomic structures of model systems of certain classes of catalysts contribute to their activity. Hrbek’s talk will review work in making models of nanometer scale particles that are the active material in many catalyst particles.


Solid surfaces often act as catalysts by binding molecules, weakening their internal bonds and allowing them to react to form new molecular products. These solid surfaces are usually nanometer-sized particles supported on micron-sized powder particles. Reacting gases or liquids flow over them to undergo reactions into the desired products. Examples of active materials include metals, metal oxides, and other metal compounds (metal sulfides and metal carbides, for example). These are known collectively as heterogeneous catalysts since they are in a separate (solid) phase from the reacting gas or liquid stream that flows over them. Very tiny particles allow most of the solid material’s atoms to be at the surface, in contact with the reacting stream. This fine dispersion is necessary to guarantee efficient use of the catalyst material. The nanometer size also is often important in improving the reactivity and selectivity of the particles. These tiny particles are often strained and the strain can promote formation of more stable active sites for a particular chemical transformation.

"Actual catalysts are very complex, not well controlled materials, often with a wide range of particle sizes and structures," Hrbek said. "It is often difficult to sort out which atomic sites are catalytically active. The goals of these model studies are to be able to determine atomic structures of the reactive sites, and to understand how reactions occur at those sites. This work ultimately aims to strengthen our ability to design better catalysts."

Among the most interesting results of the Brookhaven studies is a new method to create well-defined nanoparticles of metal compounds that are of catalytic interest.

"Reactive layer assisted deposition, or RLAD, allows us to make well-dispersed, reasonably uniform nanoparticles of metal compounds on well-defined supports," Hrbek said. "These can then be structurally characterized on the nano scale and their reactivity evaluated by using modern surface-sensitive techniques. This opens an interesting opportunity to examine catalytic activity in metal compounds that were also atomically characterized."

Several other laboratories studying nanoparticles of metal compounds have already adopted the RLAD method.

"It is a challenge to form uniform particles in this size range, to disperse them uniformly on the substrate, and to ’look’ at them with advanced microscopies to understand their structure," Hrbek said. "The tools being applied to form and study the particles are one aspect of Brookhaven’s growing capabilities in nanoscience."

Kay Cordtz | EurekAlert!
Further information:
http://www.bnl.gov

More articles from Materials Sciences:

nachricht Pressure tuned magnetism paves the way for novel electronic devices
18.12.2018 | Bar-Ilan University

nachricht Researchers observe charge-stripe crystal phase in an insulating cuprate
18.12.2018 | Boston College

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Data storage using individual molecules

Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.

Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Pressure tuned magnetism paves the way for novel electronic devices

18.12.2018 | Materials Sciences

New type of low-energy nanolaser that shines in all directions

18.12.2018 | Physics and Astronomy

NASA research reveals Saturn is losing its rings at 'worst-case-scenario' rate

18.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>