Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Road to greener chemistry paved with nano-gold

Abstract:
Nature article says gold catalysts achieve cleaner, more efficient oxidation

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

October 28, 2005

Breakthrough could "transform" chemical industry, which uses chlorine or organic peroxides in most oxidation processes. Gold nanoparticles effect insertion of oxygen atoms at selected locations along hydrocarbon molecule chains. Electron microscopy helps ensure the particles are distributed evenly over a large surface area support and prevented from coalescing. The nano-catalysts can be fine-tuned with occasional atoms of bismuth.

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."

####
Media Contact:
Kurt Pfitzer
kap4@lehigh.edu
610-758-3017

Copyright Lehigh University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Possible Futures

Sandia researchers make solid ground toward better lithium-ion battery interfaces: Reducing the traffic jam in batteries December 13th, 2017

Perking up and crimping the 'bristles' of polyelectrolyte brushes December 13th, 2017

Columbia engineers create artificial graphene in a nanofabricated semiconductor structure: Researchers are the first to observe the electronic structure of graphene in an engineered semiconductor; finding could lead to progress in advanced optoelectronics and data processing December 13th, 2017

Untangling DNA: Researchers filter the entropy out of nanopore measurements December 8th, 2017

Materials/Metamaterials

Creating a new kind of metallic glass December 7th, 2017

Copper will replace toxic palladium and expensive platinum in the synthesis of medications: The effectiveness of copper nanoparticles as a catalyst has been proven December 5th, 2017

Chinese market opens up for Carbodeon nanodiamonds: Carbodeon granted Chinese Patent for Nanodiamond-containing Thermoplastic Thermal Compounds December 4th, 2017

Scientists make transparent materials absorb light December 1st, 2017

Announcements

Sandia researchers make solid ground toward better lithium-ion battery interfaces: Reducing the traffic jam in batteries December 13th, 2017

Perking up and crimping the 'bristles' of polyelectrolyte brushes December 13th, 2017

Columbia engineers create artificial graphene in a nanofabricated semiconductor structure: Researchers are the first to observe the electronic structure of graphene in an engineered semiconductor; finding could lead to progress in advanced optoelectronics and data processing December 13th, 2017

Leti to Demo Wristband with Embedded Sensors to Diagnose Sleep Apnea: APNEAband, Which Will Be Demonstrated at CES 2018, Also Monitors Mountain Sickness, Dehydration, Dialysis Treatment Response and Epileptic Seizures December 12th, 2017

Environment

Silicon Sense first to achieve EPA approval to import detonation nanodiamonds to US: Nanodiamond additives can significantly improve the performance of metal finishing, polymer thermal and mechanical compounds, polymer coatings, CMP polishing and a range of other applications November 29th, 2017

Report highlights opportunities and risks associated with synthetic biology and bioengineering November 22nd, 2017

Dendritic fibrous nanosilica: all-in-one nanomaterial for energy, environment and health November 4th, 2017

Nano-sized gold particles have been shaped to behave as clones in biomedicine November 3rd, 2017

Industrial

Silicon Sense first to achieve EPA approval to import detonation nanodiamonds to US: Nanodiamond additives can significantly improve the performance of metal finishing, polymer thermal and mechanical compounds, polymer coatings, CMP polishing and a range of other applications November 29th, 2017

A new way to mix oil and water: Condensation-based method developed at MIT could create stable nanoscale emulsions November 8th, 2017

Researchers greenlight gas detection at room temperature October 26th, 2017

Novel 'converter' heralds breakthrough in ultra-fast data processing at nanoscale: Invention bagged four patents and could potentially make microprocessor chips work 1,000 times faster October 20th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project