Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

University of Virginia researchers uncover new catalysis site

05.08.2011
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.


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

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 & 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."

The work was funded by the U.S. Department of Energy's Office of Basic Energy Sciences.

Fariss Samarrai | EurekAlert!
Further information:
http://www.virginia.edu

More articles from Studies and Analyses:

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>