Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > New imaging technique homes in on electrocatalysis of nanoparticles

Abstract:
By modifying the rate at which chemical reactions take place, nanoparticle catalysts fulfill myriad roles in industry, the biomedical arena and everyday life. They may be used for the production of polymers and biofuels, for improving pollution and emission control devices, to enhance reactions essential for fuel cell technology and for the synthesis of new drugs. Finding new and more effective nanoparticle catalysts to perform these useful functions is therefore vital.

New imaging technique homes in on electrocatalysis of nanoparticles

Tempe, AZ | Posted on August 28th, 2012

Now Nongjian (NJ) Tao—a researcher at Arizona State University's Biodesign Institute—has found a clever way to measure catalytical reactions of single nanoparticles and multiple particles printed in arrays, which will help characterize and improve existing nanoparticle catalysts, and advance the search for new ones.

Most catalytic materials synthesized in labs contain particles with different sizes and shapes, each having different electrocatalytical activities, but the conventional methods measure the average properties of many nanoparticles, which smear out the properties of individual nanoparticles.

"The capability of measuring single nanoparticle catalytical reactions allows for determining the relationship between the efficiency of a catalytical reaction and the size, shape, and composition of the nanoparticle." Tao explained. "Such an imaging capability also makes it possible to image arrays of nanoparticle catalytical reactions, which may be used for fast screening of different nanoparticles," he added.

In the current study, platinum nanoparticles acting as electrochemical catalysts are investigated by means of the new technique, known as plasmonic electrochemical imaging. The method combines the spatial resolution of optical detection with the high sensitivity and selectivity of electrochemical recognition.

Results of the study appear in this week's advanced online edition of the journal Nature Nanotechnology.

Scanning electrochemical microscopy (SECM) has been used to image electrochemical reactions by mechanically scanning a sample surface using a microelectrode. In this process however, imaging speed is limited and the presence of the microelectrode itself may impinge on the sample and alter results.

The new method relies instead on imaging electrochemical reactions optically based on the phenomenon of surface plasmon resonance. Surface plasmons are oscillations of free electrons in a metal electrode, and can be created and detected with light. Every electrochemical reaction is accompanied by the exchange of electrons between reactants and electrodes, and the conventional electrochemical methods, including SECM, detect the electrons.

"Our approach is to measure electrochemical reactions without directly detecting the electrons." Tao said. "The trick is to detect the conversion of the reactant into reaction products associated with the exchange of electrons." Such conversion in the vicinity of the electrode affects the plasmon, causing changes in light reflectivity, which the technique converts to an optical image.

Using plasmonic electrochemical current imaging, Tao's group examined the electrocatalytic activity of platinum nanoparticles printed in a microarray on a gold thin-film electrode, demonstrating for the first time the feasibility of high-throughput screening of the catalytic activities of nanoparticles.

Additionally, the new study shows that the same method can be used to investigate individual nanoparticles. As an electrical potential is applied to the electrode and cycled through a range of values, nanoparticles clearly appear as spots on the array. The effect can be seen in accompanying videos, where nanoparticle spots ‘develop' over time as the potential changes, much like a polaroid picture gradually appears.

Microarrays featuring different surface densities of nanoparticles were also produced for the study. Results showed that electrocatalytic current at a given potential increases proportionally with nanoparticle density. Further, when individual nanoparticles were characterized using SPR microscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM), good agreement was shown between the results, further validating the new technique.

Tao notes that in principle, plasmonic electrochemical imaging— a rapid and non-invasive technique offering the combined benefits of optical and electrochemical detection—may be applied to other phenomena for which conventional electrochemical detection methods are currently used.

In addition to his appointment as the Director of the Center for Bioelectronics and Biosensors at the Biodesign Institute, Tao is Ira A. Fulton School of Engineering, School of Electrical, Computer and Energy Engineering.

####

For more information, please click here

Contacts:
Written by: Richard Harth
Science Writer: The Biodesign Institute


Joseph Caspermeyer

Copyright © Arizona State 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

News and information

Universality of charge order in cuprate superconductors: Charge order has been established in another class of cuprate superconductors, highlighting the importance of the phenomenon as a general property of these high-Tc materials December 22nd, 2014

Scientists reveal breakthrough in optical fiber communications December 21st, 2014

Atom-thick CCD could capture images: Rice University scientists develop two-dimensional, light-sensitive material December 20th, 2014

Instant-start computers possible with new breakthrough December 19th, 2014

Aculon Hires New Business Development Director December 19th, 2014

Imaging

Atom-thick CCD could capture images: Rice University scientists develop two-dimensional, light-sensitive material December 20th, 2014

Switching to spintronics: Berkeley Lab reports on electric field switching of ferromagnetism at room temp December 17th, 2014

ORNL microscopy pencils patterns in polymers at the nanoscale December 17th, 2014

Unraveling the light of fireflies December 17th, 2014

Chemistry

How does enzymatic pretreatment affect the nanostructure and reaction space of lignocellulosic biomass? December 18th, 2014

Discoveries

Universality of charge order in cuprate superconductors: Charge order has been established in another class of cuprate superconductors, highlighting the importance of the phenomenon as a general property of these high-Tc materials December 22nd, 2014

Scientists reveal breakthrough in optical fiber communications December 21st, 2014

Atom-thick CCD could capture images: Rice University scientists develop two-dimensional, light-sensitive material December 20th, 2014

Oregon researchers glimpse pathway of sunlight to electricity: Collaboration with Lund University uses modified UO spectroscopy equipment to study 'maze' of connections in photoactive quantum dots December 19th, 2014

Announcements

Universality of charge order in cuprate superconductors: Charge order has been established in another class of cuprate superconductors, highlighting the importance of the phenomenon as a general property of these high-Tc materials December 22nd, 2014

Scientists reveal breakthrough in optical fiber communications December 21st, 2014

Atom-thick CCD could capture images: Rice University scientists develop two-dimensional, light-sensitive material December 20th, 2014

Instant-start computers possible with new breakthrough December 19th, 2014

Energy

Oregon researchers glimpse pathway of sunlight to electricity: Collaboration with Lund University uses modified UO spectroscopy equipment to study 'maze' of connections in photoactive quantum dots December 19th, 2014

How does enzymatic pretreatment affect the nanostructure and reaction space of lignocellulosic biomass? December 18th, 2014

Iranian Scientists Use Nanotechnology to Increase Power, Energy of Supercapacitors December 18th, 2014

Lifeboat Foundation gives 2014 Guardian Award to Elon Musk December 16th, 2014

Automotive/Transportation

Lifeboat Foundation gives 2014 Guardian Award to Elon Musk December 16th, 2014

The gold standard December 9th, 2014

Nanocatalysts Can Reduce Pollution Caused by Diesel Engines December 4th, 2014

NEI introduces NANOMYTE® SuperAi, a Durable Anti-ice Coating December 4th, 2014

Fuel Cells

Toward a low-cost 'artificial leaf' that produces clean hydrogen fuel December 3rd, 2014

Single-atom gold catalysts may offer path to low-cost production of fuel and chemicals November 28th, 2014

National Synchrotron Light Source II Achieves 'First Light' October 23rd, 2014

Unique catalysts for hydrogen fuel cells synthesized in ordinary kitchen microwave oven October 14th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE