Home > Press > Road to greener chemistry paved with nano-gold
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."
Copyright © Lehigh University
If you have a comment, please Contact
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014
IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014
Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014
Local girl does good March 22nd, 2014
Next-Gen Luxury RV From Global Caravan Technologies Will Offer MagicView Roof and Windshield Using SPD-SmartGlass Technology From Research Frontiers: Recreational Vehicle Manufacturer Global Caravan Technologies (GCT) Features 28 Square Feet of MagicView™ SPD-SmartGlass September 17th, 2014
Nanoribbon film keeps glass ice-free: Rice University lab refines deicing film that allows radio frequencies to pass September 16th, 2014
‘Small’ transformation yields big changes September 16th, 2014
Rice rolls 'neat' nanotube fibers: Rice University researchers' acid-free approach leads to strong conductive carbon threads September 15th, 2014
FEI Opens New Technology Center in Czech Republic: FEI expands its presence in Brno with the opening of a new, larger facility September 18th, 2014
Biosensors Get a Boost from Graphene Partnership: $5 Million Investment Supports Dozens of Jobs and Development of 300mm Fabrication Process and Wafer Transfer Facility September 18th, 2014
The Pocket Project will develop a low-cost and accurate point-of-care test to diagnose Tuberculosis: ICN2 holds a follow-up meeting of the Project on September 18th - 19th September 18th, 2014
Toward making lithium-sulfur batteries a commercial reality for a bigger energy punch September 17th, 2014
Iranian Nano Scientists Create Flame-Resistant Polymers September 13th, 2014
NanoStruck has a High Recovery Rate on Mine Tailings: retrieval of up to 96% of Gold, 88% of Silver and 86% of Palladium September 12th, 2014
Nanostruck announces 87.6% recovery of 56 GMS/ton silver tailings samples September 12th, 2014
Boosting armor for nuclear-waste eating microbes September 12th, 2014
Industrial waste converted in coating for aircraft turbines September 11th, 2014
Scientists Use Nanotechnology to Improve Mechanical Properties of Ceramics September 3rd, 2014
Nanoscale assembly line August 29th, 2014
Iranians Find Novel Method for Processing Highly Pure Ceramic Nanoparticles August 12th, 2014