. Energy News .




.
CAR TECH
University of Virginia researchers uncover new catalysis site
by Staff Writers
Atlanta GA (SPX) Aug 08, 2011

Image of a dual catalytic site causing the catalytic activation of an oxygen molecule (dark blue) at the perimeter of a gold nanoparticle held on a titanium dioxide support. A carbon dioxide molecule, produced by oxidation of adsorbed carbon monoxide, is liberated. Credit: Image by Matthew Neurock, University of Virginia.

Mention catalyst and most people will think of the catalytic converter, an emissions control device in the exhaust system of automobiles that reduces pollution.

But catalysts are used for a broad variety of purposes, including the conversion of petroleum and renewable resources into fuel, as well as the production of plastics, fertilizers, paints, solvents, pharmaceuticals and more. About 20 percent of the gross domestic product in the United States depends upon catalysts to facilitate the chemical reactions needed to create products for everyday life.

Catalysts are materials that activate desired chemical reactions without themselves becoming altered in the process. This allows the catalysts to be used continuously because they do not readily deteriorate and are not consumed in the chemical reactions they inspire.

Chemists long ago discovered and refined many catalysts and continue to do so, though the details of the mechanisms by which they work often are not understood.

A new collaborative study at the University of Virginia details for the first time a new type of catalytic site where oxidation catalysis occurs, shedding new light on the inner workings of the process.

The study, conducted by John Yates, a professor of chemistry in the College and Graduate School of Arts and Sciences, and Matthew Neurock, a professor of chemical engineering in the School of Engineering and Applied Science, will be published in the Aug. 5 issue of the journal Science.

Yates said the discovery has implications for understanding catalysis with a potentially wide range of materials, since oxidation catalysis is critical to a number of technological applications.

"We have both experimental tools, such as spectrometers, and theoretical tools, such as computational chemistry, that now allow us to study catalysis at the atomic level," he said.

"We can focus in and find that sweet spot more efficiently than ever. What we've found with this discovery could be broadly useful for designing catalysts for all kinds of catalytic reactions."

Using a titanium dioxide substrate holding nanometer-size gold particles, U.Va. chemists and chemical engineers found a special site that serves as a catalyst at the perimeter of the gold and titanium dioxide substrate.

"The site is special because it involves the bonding of an oxygen molecule to a gold atom and to an adjacent titanium atom in the support," Yates said. "Neither the gold nor the titanium dioxide exhibits this catalytic activity when studied alone."

Using spectroscopic measurements combined with theory, the Yates and Neurock team were able to follow specific molecular transformations and determine precisely where they occurred on the catalyst.

The experimental and theoretical work, guided by Yates and Neurock, was carried out by Isabel Green, a U.Va. Ph.D. candidate in chemistry, and Wenjie Tang, a research associate in chemical engineering. They demonstrated that the significant catalytic activity occurred on unique sites formed at the perimeter region between the gold particles and their titania support.

"We call it a dual catalytic site because two dissimilar atoms are involved," Yates said.

They saw that an oxygen molecule binds chemically to both a gold atom at the edge of the gold cluster and a nearby titanium atom on the titania support and reacts with an adsorbed carbon monoxide molecule to form carbon dioxide. Using spectroscopy they could follow the consumption of carbon monoxide at the dual site.

"This particular site is specific for causing the activation of the oxygen molecule to produce an oxidation reaction on the surface of the catalyst," Yates said. "It's a new class of reactive site not identified before."




Related Links
University of Virginia
Car Technology at SpaceMart.com

.
Get Our Free Newsletters Via Email
...
Buy Advertising Editorial Enquiries






. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle



CAR TECH
AviCoS replaces vehicle owner manuals
Munich, Germany (SPX) Aug 08, 2011
The avatar is displayed on the monitor of the Audi Mulitmedia Interface that comes standard in all new Audi models. The virtual figure understands complete sentences. Using artificial intelligence, AviCoS interprets questions by the vehicle occupants and answers in spoken language. The driver can view descriptive images or videos on-screen and the avatar points to the relevant areas during the e ... read more


CAR TECH
Iraq power plans short-circuit

Boeing And Siemens Form Strategic Alliance for DOD Energy Modernization

Iraq PM moves to fire minister over power deals

Japan's power supply dilemma

CAR TECH
Sudan grants China oil exploration licence

UN oil devastation report to be taken 'seriously': Shell

Fusion diagnostic developed at PPPL sheds light on plasma behavior at EAST

Vietnam slams China sea survey in disputed area

CAR TECH
Scotland offshore wind farm ready to go

US fund Blackstone plans two big German wind farms

European wind power output tipped to treble by 2020: report

Estonian wind farm taps GE for turbines

CAR TECH
Solar use in Sydney soars

Solar cells get a boost from bouncing light

S. Korean firm joins Chinese solar project

ReneSola Rolls Out Shipments of Its New Multicrystalline Virtus Wafer and Module Lines

CAR TECH
Jordan to name nuclear plant builder in November

Germany's EON hit by historic quarterly loss, plans job cuts

Japan's TEPCO logs $7.4bn quarterly loss

Bayer chief warns firms may leave Germany over energy costs

CAR TECH
Ethanol-loving bacteria accelerate cracking of pipeline steels

A new catalyst for ethanol made from biomass

Scientists find way to identify manmade biofuels in atmosphere

Growth slowing in EU biofuels market

CAR TECH
Why Tiangong is not a Station Hub

China to launch experimental satellite in coming days

Spotlight Time for Tiangong

China launches new data relay satellite

CAR TECH
Fleeing famine, Somalis queue patiently for a cooked meal

Slowing climate change by targeting gases other than carbon dioxide

Kenyans fundraise for drought, rap government

Human Influence on the 21st Century Climate


Memory Foam Mattress Review
Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News
.

The content herein, unless otherwise known to be public domain, are Copyright 1995-2011 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement