Featured Research

from universities, journals, and other organizations

Tiny Gold Clusters Are Top-notch Catalysts

Date:
September 8, 2008
Source:
National Institute of Standards and Technology
Summary:
Using a pair of scanning transmission electron microscopy instruments for which spherical aberration is corrected, researchers have for the first time achieved state-of-the-art resolution of gold nanocrystals absorbed onto iron oxide surfaces that can catalyzed a variety of reactions, including the oxidation of carbon monoxide to carbon dioxide.

Electron micrographs showing inactive (left) and active (right) catalysts consisting of gold particles absorbed on iron oxide. The red circles indicate the presence of individual gold atoms. The yellow circles show the location of subnanometer gold clusters that can effectively catalyze the conversion of carbon monoxide to carbon dioxide. One nanometer is about half the size of a DNA molecule. (Color added for clarity)
Credit: Lehigh University Center for Advanced Materials and Nanotechnology

For most of us, gold is only valuable if we possess it in large-sized pieces. However, the "bigger is better" rule isn't the case for those interested in exploiting gold's exceptional ability to catalyze a wide variety of chemical reactions, including the oxidation of poisonous carbon monoxide (CO) into harmless carbon dioxide at room temperatures.

That process, if industrialized, could potentially improve the effectiveness of catalytic converters that clean automobile exhaust and breathing devices that protect miners and firefighters. For this purpose, nanoclusters—gold atoms bound together in crystals smaller than a strand of DNA—are the size most treasured.

Using a pair of scanning transmission electron microscopy (STEM) instruments for which spherical aberration (a system fault yielding blurry images) is corrected, researchers at the National Institute of Standards and Technology (NIST), Lehigh University (Bethlehem, Pa.) and Cardiff University (Cardiff, Wales, United Kingdom) for the first time achieved state-of-the-art resolution of the active gold nanocrystals absorbed onto iron oxide surfaces. In fact, the resolution was sensitive enough to even visualize individual gold atoms.

Surface science studies have suggested that there is a critical size range at which gold nanocrystals supported by iron oxide become highly active as catalysts for CO oxidation. However, the theory is based on research using idealized catalyst models made of gold absorbed on titanium oxide. The NIST/Lehigh/Cardiff aberration-corrected STEM imaging technique allows the researchers to study the real iron oxide catalyst systems as synthesized, identify all of the gold structures present in each sample, and then characterize which cluster sizes are most active in CO conversion.

The research team discovered that size matters a lot—samples ranged from those with little or no catalytic activity (less than 1 percent CO conversion) to others with nearly 100 percent efficiency. Their results revealed that the most active gold nanoclusters for CO conversion are bilayers approximately 0.5-0.8 nanometer in diameter (40 times smaller than the common cold virus) and containing about 10 gold atoms. This finding is consistent with the previous surface science studies done on the gold-titanium oxide models.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology. Note: Materials may be edited for content and length.


Journal Reference:

  1. A.A. Herzing, C.J. Kiely, A.F. Carley, P. Landon and G.J. Hutchings. Identification of active gold nanoclusters on iron oxide supports for CO oxidation. Science, Vol. 321, Issue 5894, Sept. 5, 2008

Cite This Page:

National Institute of Standards and Technology. "Tiny Gold Clusters Are Top-notch Catalysts." ScienceDaily. ScienceDaily, 8 September 2008. <www.sciencedaily.com/releases/2008/09/080905215954.htm>.
National Institute of Standards and Technology. (2008, September 8). Tiny Gold Clusters Are Top-notch Catalysts. ScienceDaily. Retrieved April 18, 2014 from www.sciencedaily.com/releases/2008/09/080905215954.htm
National Institute of Standards and Technology. "Tiny Gold Clusters Are Top-notch Catalysts." ScienceDaily. www.sciencedaily.com/releases/2008/09/080905215954.htm (accessed April 18, 2014).

Share This



More Matter & Energy News

Friday, April 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Small Reactors Could Be Future of Nuclear Energy

Small Reactors Could Be Future of Nuclear Energy

AP (Apr. 17, 2014) After the Fukushima nuclear disaster, the industry fell under intense scrutiny. Now, small underground nuclear power plants are being considered as the possible future of the nuclear energy. (April 17) Video provided by AP
Powered by NewsLook.com
Horseless Carriage Introduced at NY Auto Show

Horseless Carriage Introduced at NY Auto Show

AP (Apr. 17, 2014) An electric car that proponents hope will replace horse-drawn carriages in New York City has also been revealed at the auto show. (Apr. 17) Video provided by AP
Powered by NewsLook.com
Honda's New ASIMO Robot, More Human-Like Than Ever

Honda's New ASIMO Robot, More Human-Like Than Ever

AFP (Apr. 17, 2014) It walks and runs, even up and down stairs. It can open a bottle and serve a drink, and politely tries to shake hands with a stranger. Meet the latest ASIMO, Honda's humanoid robot. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
German Researchers Crack Samsung's Fingerprint Scanner

German Researchers Crack Samsung's Fingerprint Scanner

Newsy (Apr. 16, 2014) German researchers have used a fake fingerprint made from glue to bypass the fingerprint security system on Samsung's new Galaxy S5 smartphone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins