Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > A nano-sized sponge made of electrons: X-rays reveal an unexpected property of widely used nanoparticles

Time dependent cerium high energy resolution fluorescence detection X-ray adsorption spectroscopy (HERFD-XAS) of 3nm cerium dioxide particles before any chemical reaction (red curve) and during the catalase mimetic activity (bleu curve).
Time dependent cerium high energy resolution fluorescence detection X-ray adsorption spectroscopy (HERFD-XAS) of 3nm cerium dioxide particles before any chemical reaction (red curve) and during the catalase mimetic activity (bleu curve).

Abstract:
A new chapter has been opened in our understanding of the chemical activity of nanoparticles says a team of international scientists. Using the X-ray beams of the European Synchrotron ESRF they showed that the electrons absorbed and released by cerium dioxide nanoparticles during chemical reactions behave in a completely different way than previously thought: the electrons are not bound to individual atoms but, like a cloud, distribute themselves over the whole nanoparticle. Inspired by the similarity of its shape, the scientists call this spatial distribution of particles an "electron sponge". The results were published on 12 November in the journal ACS Nano.

A nano-sized sponge made of electrons: X-rays reveal an unexpected property of widely used nanoparticles

Grenoble, France | Posted on November 12th, 2013

The team of scientists was led by Pieter Glatzel from The European Synchrotron (ESRF) in Grenoble (France) and Victor Puntes from the Universitá Autònoma of Barcelona, Catalan Institute of Nanotechnologies (Spain). The first author is Jean-Daniel Cafun from the ESRF.

Today, cerium dioxide nanoparticles are widely used in industrial processes and also in consumer products. They are present, for example, in the walls of self-cleaning ovens and act as a hydrocarbon catalyst during the high temperature cleaning process. They are also a hot candidate for the next generation of lithium-ion batteries which will exhibit higher voltages and a greater storage capacity compared to today's energy cells.

The element Cerium is abundant in the Earth's crust and can easily be mined and purified. However, without a thorough understanding of the chemical processes happening on the surface of cerium dioxide nanoparticles, it is impossible to optimise their current and future use. And to address a more complex issue, it is also impossible to assess the limits of their safe use.

Most chemical reactions involve the transfer of an electron from one atom to another. In the past, it was believed that the electrons involved in a chemical reaction on the surface of a nanoparticle were localised in one of the atoms at the surface. To determine the behaviour of the electrons during the reaction, the scientists used the intense X-ray beams at the ESRF to probe solutions of nanoparticles in water and ethanol. The nanoparticles had a diameter of 3 nm and consisted of several thousands of molecules of cerium dioxide.

It is known that nanoparticles can change their behaviour under vacuum when studied with an electron microscope, for example. The scientists therefore carried out their experiment under realistic conditions, studying the nanoparticles in solution and in real time as the chemical reaction was taking place. "It was only possible to conduct these experiments in a liquid rather than under vacuum because we used X-rays as probes for the electron distribution." says Jean Daniel Cafun.

In their experiment, the scientists were successful in observing the creation of the nanoparticles in solution and then how these nanoparticles eliminated highly reactive molecules (reactive oxygen species, or ROS) from the solution. This elimination process mimics the role of an important enzyme in living organisms - catalase - that protects cells from these aggressive molecules. Cancer patients undergoing radiation therapy have high levels of ROS in their bodies and ceria nanoparticles have been proposed as a way of reducing the levels of ROS and thus alleviating the negative impacts of the therapy on the patients. Throughout the chemical reaction, the electronic structure of the cerium atoms and thus the redistribution of the electron cloud was monitored. "It is crucial to be able to study the chemical processes of the particles in an environment that is close to conditions found in biological systems." emphasizes Victor Puntes.

"Scientists have been discussing the question: What happens when electrons are added to ceria nanoparticles? The work by Cafun et al. is a key study because it questions the present, widely accepted model and will lead the research in a new direction." says Frank de Groot, an expert on nanomaterials at Utrecht University who did not take part in the experiment.

The next step, which has already been initiated, will be to assess whether non-localised electrons are a property of cerium dioxide only or also of other widely used nanoparticles like titanium dioxide. "In parallel, chemists have to revisit their theoretical models to explain the chemical behaviour of nanoparticles and to better understand how electrons are transferred in chemical reactions taking place on their surface." concludes Pieter Glatzel.

####

For more information, please click here

Contacts:
Claus Habfast

33-666-662-384

Copyright © European Synchrotron Radiation Facility

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 Links

Reference:

Related News Press

News and information

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Deep Space Industries and SFL selected to provide satellites for HawkEye 360’s Pathfinder mission: The privately-funded space-based global wireless signal monitoring system will be developed by Deep Space Industries and UTIAS Space Flight Laboratory May 26th, 2016

The next generation of carbon monoxide nanosensors May 26th, 2016

Imaging

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Carnegie Mellon develops bio-mimicry method for preparing and labeling stem cells: Method allows researchers to prepare mesenchymal stem cells and monitor them using MRI May 19th, 2016

Chemistry

Syracuse University chemists add color to chemical reactions: Chemists in the College of Arts and Sciences have come up with an innovative new way to visualize and monitor chemical reactions in real time May 19th, 2016

Technique improves the efficacy of fuel cells: Research demonstrates a new phase transition from metal to ionic conductor May 18th, 2016

Physicists measure van der Waals forces of individual atoms for the first time May 14th, 2016

Discoveries

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Announcements

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Deep Space Industries and SFL selected to provide satellites for HawkEye 360’s Pathfinder mission: The privately-funded space-based global wireless signal monitoring system will be developed by Deep Space Industries and UTIAS Space Flight Laboratory May 26th, 2016

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Tools

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Light can 'heal' defects in new solar cell materials: Defects in some new electronic materials can be removed by making ions move under illumination May 24th, 2016

More light on cancer: Scientists created nanoparticles to highlight cancer cells May 21st, 2016

Nanotubes are beacons in cancer-imaging technique: Rice University researchers use spectral triangulation to pinpoint location of tumors May 21st, 2016

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







Car Brands
Buy website traffic