Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Road to greener chemistry paved with nano-gold, researchers report

25.10.2005


’Nature’ article says gold catalysts achieve cleaner, more efficient oxidation



The selective oxidation processes that are used to make compounds contained in agrochemicals, pharmaceuticals and other chemical products can be accomplished more cleanly and more efficiently with gold nanoparticle catalysts, researchers have reported in Nature magazine.

A team of 13 U.K. researchers and one U.S. researcher reported in the Oct. 20 issue of the British journal that the carbon-supported gold catalysts can be fine-tuned with high selectivity for desired products through the addition of trace amounts of bismuth.


The gold catalysts can also carry out partial oxidations under solvent-free conditions, the researchers said, making them more environmentally friendly than oxidation processes that use chlorine, and less costly than those employing organic peroxides.

The team, led by Graham Hutchings, professor of physical chemistry at Cardiff University in Wales, included eight other Cardiff chemists, four scientists from the Johnson Matthey chemical company in the United Kingdom, and a materials scientist from Lehigh University in Bethlehem, Pennsylvania.

Their article was titled "Tuneable gold catalysts for selective hydrocarbon oxidation under mild conditions."

Masatake Haruta, a catalyst chemist at Tokyo Metropolitan University who has been at the forefront of gold nanoparticles research for more than a decade, said in a commentary accompanying the Nature article that the breakthrough by Hutchings’s group had the potential to "transform" the chemical industry.

Noting that most industrial oxidation processes use chlorine or organic peroxides, Haruta said, "the chemical industry would be transformed if selective oxidation of hydrocarbons could be achieved efficiently using cheap and clean oxygen from the air. The advancement by Hutchings and colleagues of ’greener’ methods for oxidation catalysis using gold is therefore invaluable."

The industrial selective oxidation processes that Hutchings’s team catalyzed with gold nanoparticles are used to convert unsaturated hydrocarbons to oxygen-containing organic compounds (e.g., epoxides, ketones), which in turn serve as higher-value compounds that form the basis for many chemical products.

The challenge, says Chris Kiely, professor of materials science and engineering at Lehigh University, is to selectively insert an oxygen atom at specific positions into long-chain or cyclic-ring hydrocarbon carbon molecules, something which nanoparticulate gold achieves effectively.

The gold nanoparticles, which measure 2 to 15 nanometers in width (1 nm equals one one-billionth of a meter) must be distributed evenly over a large surface area support and prevented from coalescing and forming larger particles with weaker catalytic properties.

"The nano-gold catalyst can effectively aid the insertion of an oxygen atom into the unsaturated hydrocarbon," says Kiely, who has co-authored several dozen papers with Hutchings. "Activated carbon provides a viable support for the nanoparticles. The gold catalyst can also be fine-tuned and made more effective, giving a higher yield of epoxides and ketones, with the addition of occasional atoms of bismuth.

"We’re trying to determine the size, distribution and shape of the gold nanoparticles, and to see how these parameters relate to the measured catalytic properties. We are also interested in the interaction of gold with other promoter elements, such as bismuth, and we’re trying to identify exactly where the bismuth atoms are going and why they have a beneficial effect."

Kiely, who joined the Lehigh faculty in 2002 after serving on the materials science and engineering and chemistry faculties at Liverpool University, uses transmission electron microscopy and various spectroscopic techniques to characterize the gold nanoparticles.

The recent acquisition by Lehigh University of two aberration-corrected electron microscopes, including a JEOL 2200FS transmission electron microscope, will shed more light on future work in the area of gold catalysis, he said.

"Before, we were able to see nanoparticles and achieve atomic resolution, but not with the same degree of clarity that the new JEOL microscope provides. The new instrument also gives us the capability of doing chemical composition analysis with close to atomic column precision, which will be a big boon."

Gold in recent years has drawn more attention from researchers as a potential catalyst in chemical processing, pollution control and fuel cell applications. Haruta, a pioneer in this area, demonstrated a decade ago that gold nanoparticles could be used, amongst other things, as catalysts to de-odorize restrooms and to convert carbon monoxide to carbon dioxide at low temperatures.

But much remains to be learned for nano-gold to realize its full potential, says Kiely, who directs the Nanocharacterization Laboratory in Lehigh’s Center for Advanced Materials and Nanotechnology.

"Gold is a very useful catalyst for many chemical reactions," says Kiely, "but we’re still not sure what happens at the molecular scale during the catalysis process. The more we learn, the better we can fine-tune gold nanoparticle catalysts."

Kurt Pfitzer | EurekAlert!
Further information:
http://www.lehigh.edu

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

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 >>>