Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Platinum and iron oxide working together get the job done: Scientists at the Vienna University of Technology (TU Wien) have figured out how a platinum catalyst works -- its remarkable properties are not just due to the platinum, the iron-oxide substrate beneath also plays a role

This is the Surface Science Lab at TU Wien (Vienna) - vacuum chamber.
CREDIT: TU Wien
This is the Surface Science Lab at TU Wien (Vienna) - vacuum chamber.

CREDIT: TU Wien

Abstract:
Platinum is a great catalyst and can be used for many different applications. It's expensive stuff though, so tiny platinum nanoparticles sitting on cheap metal oxide materials are used to convert harmful carbon monoxide into carbon dioxide. Using scanning tunnelling microscopes, scientists at TU Vienna have now been able to image the catalytic behaviour of platinum sitting on iron-oxide, which allowed them to explain the process on an atomic scale. Surprisingly, the chemical reactions do not take place on the platinum nanoparticles themselves, and it is the interplay between platinum particles and the iron-oxide surface that makes the reaction so efficient.

Platinum and iron oxide working together get the job done: Scientists at the Vienna University of Technology (TU Wien) have figured out how a platinum catalyst works -- its remarkable properties are not just due to the platinum, the iron-oxide substrate beneath also plays a role

Vienna, Austria | Posted on September 17th, 2015

Catching and Oxidising Molecules

The tiny nanoparticles used for catalysis often consist of only a few platinum atoms. They enable oxidation by keeping target molecules in place and bringing them into contact with oxygen. That way, carbon monoxide (CO) can be turned into carbon dioxide (CO2), hydrogen gas (H2) is oxidized to water (H2O). These reactions are also possible without platinum, but they can occur at much lower temperatures in the presence of platinum particles.

"We used to believe that these chemical reactions occur right on top of the platinum particles. But our pictures clearly show that the iron oxide really does the job", says Professor Gareth Parkinson. For years he has been studying the behaviour of tiny particles on metal-oxide surfaces together with Professor Ulrike Diebold (both TU Vienna). Now the team could show that the oxygen needed for the chemical reactions does not originate from the surrounding atmosphere but from the iron oxide below.

Nano-Holes and Travelling Iron

The iron oxide (Fe3O4), on which the platinum particles rest, has remarkable properties. It has a regular crystal structure and each atom has its well-defined position, but still the iron atoms are relatively free to travel through the material. When the platinum nanoparticles catch molecules from the surrounding gas and combine them with oxygen atoms from the iron-oxide surface, a surplus of iron atoms remains. These iron atoms then migrate deep into the material, leaving a hole in the surface that can clearly be seen in the pictures taken with the scanning tunnelling microscope.

This process can even trigger a chain reaction. As soon as the chemical reaction at the platinum nanoparticle creates a hole in the iron-oxide surface, there are some atoms right at the edge of the hole whose coupling to the rest of the material is not very strong. At these edges the next chemical reaction can occur much more easily. The platinum nanoparticle is shifted slightly and it is ready for the next step. "In the end, we can see long trenches on the surface, left behind by a single platinum nanoparticle", says Ulrike Diebold.

The opposite phenomenon occurs when platinum and iron-oxide is exposed to an oxygen atmosphere. The platinum particles break up the oxygen molecules (O2), and the single oxygen atoms can then be integrated into the surface. Iron atoms travel to the surface from within the material, and right next to the platinum nanoparticle, an additional iron-oxide island is created. Instead of holes, many small islands grow on the surface.

Towards Better Catalysts

For years the team at TU Vienna has been working hard to lay the necessary groundwork for this kind of research. In many important steps the surface-science team perfected ways to handle metal oxides and tiny particles. In recent years, the have presented important new findings about the structure of metal oxides, about the mobility of atoms on their surface and their chemical properties. Based on this experience, it is now possible to make the chemical processes of platinum catalysis visible and to explain them in detail.

Now this new knowledge can be used to create even better catalysts. For instance, the team could show that pre-treating with hydrogen should increase the efficiency of platinum catalysts. The atomic trenches created that way keep the platinum nanoparticles from clustering, which would decrease their reactivity.

####

For more information, please click here

Contacts:
Florian Aigner

43-158-801-41027

Copyright © Vienna University of Technology

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

Chemistry

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

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

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

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

Materials/Metamaterials/Magnetoresistance

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

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

Focused ion beam technology: A single tool for a wide range of applications January 12th, 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

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

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

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

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

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

Automotive/Transportation

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

New designs for solid-state electrolytes may soon revolutionize the battery industry: Scientists achieve monumental improvements in lithium-metal-chloride solid-state electrolytes November 3rd, 2023

Previously unknown pathway to batteries with high energy, low cost and long life: Newly discovered reaction mechanism overcomes rapid performance decline in lithium-sulfur batteries September 8th, 2023

Tests find no free-standing nanotubes released from tire tread wear September 8th, 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