Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > 2 for 1: Simultaneous size and electrochemical measurement of nanomaterials

Schematic of NIST's "eSANS" (electrochemical Small-Angle Neutron Scattering) cell. A highly porous, sponge-like carbon electrode maximizes surface area for electrochemical reactions while structural details like particle size and configuration are measured using neutron scattering (image at left).

Credit: Prabhu/NIST
Schematic of NIST's "eSANS" (electrochemical Small-Angle Neutron Scattering) cell. A highly porous, sponge-like carbon electrode maximizes surface area for electrochemical reactions while structural details like particle size and configuration are measured using neutron scattering (image at left).

Credit: Prabhu/NIST

Abstract:
Researchers at the National Institute of Standards and Technology (NIST) have done a mash-up of two very different experimental techniques—neutron scattering and electrochemical measurements—to enable them to observe structural changes in nanoparticles as they undergo an important type of chemical reaction. Their recently published technique* allows them to directly match up particle size, shape and agglomeration with the "redox" chemical properties of the particles. The measurements are important both for the design of nanoparticles for particular applications and for toxicology studies.

2 for 1: Simultaneous size and electrochemical measurement of nanomaterials

Gaithersburg, MD | Posted on March 7th, 2012

Nanoparticles present unique engineering challenges—and opportunities—because their extremely small size can give them physical properties quite unlike those they have in bulk quantities. The challenge for materials scientists is to determine just what those changes are and how they relate to particle size and structure.

The NIST team was interested in the oxidation-reduction—redox— properties of zinc oxide nanoparticles, which are used or being considered for a wide variety of applications ranging from sunscreens and antibacterial coatings to semiconductor and photoelectronic devices.

Redox reactions are one of the major divisions of chemical reactions, those that involve a transfer of electrons from one atom or molecule to another. Redox properties determine the path a chemical reaction will take. "They are the drivers of many biological processes," explains NIST materials researcher Vivek Prabhu. "There are many biochemical reactions that are well-defined oxidation-reduction reactions. There are tables of these. But there are no such tables that we know of on how nanoparticles can affect those reactions."

The NIST team knew they could monitor the size, shape and dispersion of nanoparticles in solution using SANS—small-angle neutron scattering. The scattering patterns from a SANS instrument, says Prabhu, give you not only those details but structural information about the solution itself, the size distribution of the particles and whether they clump together, all in "real" time as the experiment progresses.

Redox properties, on the other hand, are measured in electrochemical cells that are essentially half of a battery. Voltage and the amount of current flowing through the primary electrode depend on the reaction redox potential and the concentration of the test material.

The problem, Prabhu explains, is that SANS measures things in bulk, in a volume of space, but, "An electrochemical experiment is a very local experiment—it happens at an interface. What we needed was to maximize the interface." The answer, contributed by his partner, Vytas Reipa, is an exotic material called reticulated glassy carbon. "Like a very stiff household sponge or scouring pad made of pure carbon," Prabhu explains. The porous carbon electrode turned out to be an ideal terminal—lots of surface area to serve as a reaction interface; nearly transparent to neutrons, so it doesn't contribute much background noise; and best of all, it works well in water, enabling the study of nanoparticles in aqueous solutions, critical for biological reactions.

A big advantage of the "eSANS" technique, Prabhu says, is its generality. "You can apply our method to nearly any dispersed material that is of interest to redox chemistry—polymers, redox proteins, nucleic acids—at this nanoscale. Small polymer chains, for example. You can't really see them with electron microscopy, you can with neutrons."

* V.M. Prabhu and V. Reipa. In situ electrochemical small-angle neutron scattering (eSANS) for quantitative structure and redox properties of nanoparticles. J. Phys. Chem. Lett. 2012, 3, 646-650 dx.doi.org/10.1021/jz300124t.

####

For more information, please click here

Contacts:
Michael Baum

301-975-2763

Copyright © National Institute of Standards and Technology (NIST)

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

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Leti Presents Advances in Propagation Modeling and Antenna Design for mmWave Spectrum: Paper Is One of 15 that Leti Presented at European Conference on Antennas and Propagation March 19-24 March 23rd, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Laboratories

Researchers develop groundbreaking process for creating ultra-selective separation membranes: Discovery could greatly improve energy-efficiency of separation and purification processes in the chemical and petrochemical industries March 15th, 2017

Discovery in new material raises questions about theoretical models of superconductivity March 13th, 2017

Perovskite edges can be tuned for optoelectronic performance: Layered 2D material improves efficiency for solar cells and LEDs March 10th, 2017

Imaging the inner workings of a sodium-metal sulfide battery for first time: Understanding how the structural and chemical makeup of the material changes during the charge/discharge process could help scientists advance battery design for future energy storage needs March 9th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Nanobiotix: The Independent Data Monitoring Committee Recommends the Continuation of the Ongoing Phase II/III Trial of NBTXR3 in Soft Tissue Sarcoma March 23rd, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Discoveries

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Announcements

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Tools

Caught on camera -- chemical reactions 'filmed' at the single-molecule level March 22nd, 2017

CRMGroup in Belgium uses a Deben three point bending stage in the development of new steel & coated steel products for automotive and other industrial applications March 21st, 2017

Next-gen steel under the microscope March 18th, 2017

Novel nozzle saves crystals: Double flow concept widens spectrum for protein crystallography March 17th, 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