Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



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

Researchers develop artificial building blocks of life March 8th, 2024

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

Two-dimensional bimetallic selenium-containing metal-organic frameworks and their calcinated derivatives as electrocatalysts for overall water splitting March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

Laboratories

A battery’s hopping ions remember where they’ve been: Seen in atomic detail, the seemingly smooth flow of ions through a battery’s electrolyte is surprisingly complicated February 16th, 2024

NRL discovers two-dimensional waveguides February 16th, 2024

Catalytic combo converts CO2 to solid carbon nanofibers: Tandem electrocatalytic-thermocatalytic conversion could help offset emissions of potent greenhouse gas by locking carbon away in a useful material January 12th, 2024

Three-pronged approach discerns qualities of quantum spin liquids November 17th, 2023

Govt.-Legislation/Regulation/Funding/Policy

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024

Discoveries

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

High-tech 'paint' could spare patients repeated surgeries March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Announcements

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Tools

First direct imaging of small noble gas clusters at room temperature: Novel opportunities in quantum technology and condensed matter physics opened by noble gas atoms confined between graphene layers January 12th, 2024

New laser setup probes metamaterial structures with ultrafast pulses: The technique could speed up the development of acoustic lenses, impact-resistant films, and other futuristic materials November 17th, 2023

Ferroelectrically modulate the Fermi level of graphene oxide to enhance SERS response November 3rd, 2023

The USTC realizes In situ electron paramagnetic resonance spectroscopy using single nanodiamond sensors November 3rd, 2023

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project