Featured Research

from universities, journals, and other organizations

New Method Can Capture Catalysis, One Molecule At A Time

Date:
November 12, 2008
Source:
Cornell University
Summary:
Researchers have developed an ingenious microscopic method to observe the behavior of single nanoparticles of a catalyst, down to the resolution of single catalytic events.

Graphic of nanoparticle catalysis. When a molecule of resazurin dye (on top of the particle) binds to the gold nanoparticle it is changed to highly fluorescent resorufin (in front of the particle) by removal of an oxygen atom (moving away to the right). Resorufin glows under ultraviolet light. A graph of the time it spends before releasing from the gold surface reveals details about how the reaction takes place.
Credit: Graphic by Aleksandr Kalininskiy

Cornell researchers have developed an ingenious microscopic method to observe the behavior of single nanoparticles of a catalyst, down to the resolution of single catalytic events.

Their observations have shown that not all nanoparticles in a batch are created equal: Some carry out their reactions in different ways than others. The researchers have also directly observed that every nanoparticle changes the speed of its catalytic reaction over time, and they have measured the time scale.

There is intense interest in nanocatalysts for such applications as fuel cells and pollutant removal, because nanoparticles provide a larger surface area to speed reactions, and in some cases, materials that are not catalytic in bulk become so at the nanoscale.

"Understanding the fundamental principles that govern the catalyst activity can help us to design new catalysts," said Peng Chen, Cornell assistant professor of chemistry and chemical biology. "Nanoparticles are dynamic entities. Maybe we can think about designing smart catalysts that can adapt to different conditions."

The research by Chen and colleagues is described in the online edition of the journal Nature Materials and will appear in a forthcoming print edition.

The researchers immobilized spherical gold nanoparticles about 6 nanometers in diameter on a glass surface and flowed a solution of a dye over them. The gold catalyst changes molecules of the dye into a new fluorescent form. Using a microscope that focuses on a very thin plane, the researchers made a "movie" with one frame every 30 milliseconds.

A dye molecule briefly binds to the surface of the gold, where an oxygen atom is removed. The new molecule fluoresces, and a blip of light appears in the microscope image, remaining until the molecule releases from the catalyst. The researchers were able to isolate the blips from individual nanoparticles and identify single catalytic events.

They saw two slightly different reaction patterns: On some nanoparticles the dye molecule binds to the surface, is changed and then releases. On others, after the change the molecule moves to a new position before it releases. And on some nanoparticles, both types of reaction occur. The nanoparticles, Chen explained, are not perfectly spherical, and different parts of the gold crystal are exposed at different places on the surface; this may account for the different reaction patterns.

Reactions at the same sites also varied in their timing. The time a fluorescent molecule remains at a given site might be short, then longer, then short again. The explanation, the researchers said, is that the catalytic reaction also causes a restructuring of the surface of the gold, and this causes the subsequent reactions to take place faster or slower. Later, the gold surface recovers to its original structure, and the reaction returns to its original timing.

"For the first time, we could provide a quantitation on the restructuring timescales at tens to hundreds of seconds," the researchers said.

The research was supported by the Cornell Center for Materials Research, funded by the National Science Foundation, and by the Petroleum Research Foundation of the American Chemical Society.


Story Source:

The above story is based on materials provided by Cornell University. Note: Materials may be edited for content and length.


Cite This Page:

Cornell University. "New Method Can Capture Catalysis, One Molecule At A Time." ScienceDaily. ScienceDaily, 12 November 2008. <www.sciencedaily.com/releases/2008/11/081110170318.htm>.
Cornell University. (2008, November 12). New Method Can Capture Catalysis, One Molecule At A Time. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2008/11/081110170318.htm
Cornell University. "New Method Can Capture Catalysis, One Molecule At A Time." ScienceDaily. www.sciencedaily.com/releases/2008/11/081110170318.htm (accessed July 30, 2014).

Share This




More Matter & Energy News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
China's Drone King Says the Revolution Depends on Regulators

China's Drone King Says the Revolution Depends on Regulators

Reuters - Business Video Online (July 30, 2014) Comparing his current crop of drones to early personal computers, DJI founder Frank Wang says the industry is poised for a growth surge - assuming regulators in more markets clear it for takeoff. Jon Gordon reports. Video provided by Reuters
Powered by NewsLook.com
3Doodler Bring 3-D Printing to Your Hand

3Doodler Bring 3-D Printing to Your Hand

AP (July 30, 2014) 3-D printing is a cool technology, but it's not exactly a hands-on way to make things. Enter the 3Doodler: the pen that turns you into the 3-D printer. AP technology writer Peter Svensson takes a closer look. (July 30) Video provided by AP
Powered by NewsLook.com
Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. 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