Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A new perspective for understanding the mechanisms of catalytic conversion

09.02.2010
The oxidation of toxic carbon monoxide (CO) to carbon dioxide occurs every day in millions of cars. Despite being one of the most studied catalytic processes, the exact mechanism of interaction between the carbon monoxide molecule and the catalyst, often platinum, is not fully understood.

An important step in the reaction is the adsorption of CO on the surface of the catalyst. A team of scientists from the ESRF and the ETH in Zurich (Switzerland) has managed to see how the electrons in the platinum reorganize as the adsorption is taking place and why catalysts are “poisoned”, i.e. why their activity is reduced. It is the first time that this type of experiment is carried out at the same high temperatures and pressures as in a real car exhaust catalyst.

When the CO or other toxic gases get in contact with the catalyst, a noble metal such as platinum, they oxidize to become less dangerous gases. In this case, CO turns to CO2, which the car expels via the exhaust pipe. However, the efficiency of the catalytic conversion decreases considerably when the catalyst is at low temperature. The scientists from the ESRF and ETH in Zurich determined how the CO poisons the surface of the catalyst. The strong bond between CO and the platinum blocks active sites and makes the metal less susceptible to reaction with oxygen, lowering its reactivity.

Scientists around the world have studied thoroughly the electron structure of adsorbed CO using techniques like vibration and soft X-ray spectroscopy, but few have studied the electrons in the platinum, and it has proven extremely difficult to do it on nanoparticles under ambient pressure. In fact, very few experimental techniques are compatible with the required temperature, gas environment, and the low metal concentration of supported nanoparticles.

The team has developed a technique where they can investigate the platinum electrons that take part in the bond with CO. “We have, for the first time, combined a novel experimental and theoretical approach with an important application in catalysis research. This enables us to look at the adsorption of CO on Pt nanoparticles from a new perspective that was previously not accessible” explains Pieter Glatzel, scientist at the ESRF.

The next step is to look at the changes in catalyst structure under actual catalytic conditions, such as those occurring during the preferential oxidation of CO and the water gas shift reaction. “We are very hopeful of this new technique and are sure that it will enable us to improve our knowledge about catalytic systems and, with it, make them better”, says Jeroen van Bokhoven, scientist at the ETH.

Montserrat Capellas | alfa
Further information:
http://www.esrf.fr
http://www.esrf.fr/news/general/platinum/

More articles from Ecology, The Environment and Conservation:

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>