Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dynamic catalytic converters for clean air in the city

27.10.2017

Dynamic structure of platinum particles optimizes exhaust gas aftertreatment, German-French cooperation, publication in the journal 'Angewandte Chemie'

Reducing pollutant emission of vehicles and meeting stricter exhaust gas standards are major challenges when developing catalytic converters. A new concept might help to efficiently treat exhaust gases after the cold start of engines and in urban traffic and to reduce the consumption of expensive noble metal.


The catalytic converter of a car converts toxic carbon monoxide (CO) into non-toxic carbon dioxide (CO2) and consists of cerium (Ce), oxygen (O), and platinum (Pt).

Figure: Gänzler/KIT

It is based on the interaction between platinum and the cerium oxide carrier to control catalytic activity by short-term changes of the engine's operation mode, researchers report in the journal Angewandte Chemie (Applied Chemistry).

Thanks to its good catalytic properties, platinum is often applied in catalytic converters of vehicles. Presently, about 60% of European platinum trade are used for this purpose. Using a diesel oxidation catalytic converter (DOC), in which afterburning of hydrocarbons and carbon monoxide takes place, the scientists of Karlsruhe Institute of Technology (KIT) and their partners found that the particle size and oxidation state of the platinum component during operation can be modified specifically.

Interactions between the carrier material and the applied noble metal play an important role. The results reflect a highly dynamic catalytic converter surface that reacts extremely sensitively to external impacts, such as exhaust gas composition. The researchers present ways of using this dynamics to improve catalytic converters.

"The special thing is that we can adjust the size and state of the noble metal nanoparticles on the surface of the catalytic converter. The methods enable us to do this under relevant and even real operation conditions and, hence, to directly adjust the catalytic activity of materials," says Andreas Gänzler, scientist of KIT's Institute for Chemical Technology and Polymer Chemistry (ITCP) and main author of the study "Tuning the Structure of Platinum Particles on Ceria In Situ for Enhancing the Catalytic Performance of Exhaust Gas Catalysts" published in the latest issue of the journal Angewandte Chemie (Applied Chemistry).

In their study, the researchers demonstrated how sensitively the state of platinum reacts to the composition, i.e. the ratio of carbon monoxide and oxygen, and the temperature of the exhaust gas. Engine operation already is modified specifically in exhaust gas aftertreatment systems used today. In this way, exhaust gas composition is adjusted for the regeneration of particulate filters or NOx storage catalytic converters. The study reveals that it is also possible to optimally set the active platinum component in order to enhance activity of the catalytic converter and reduce the consumption of noble metal.

In the course of the German-French cooperation project, complex methods were used to observe the materials under operation conditions. By means of environmental transmission electron microscopy (ETEM), structural modifications on the atomic level of the material were visualized. X-ray absorption spectroscopy at the SOLEIL synchrotron in the French St. Aubin and at the KARA Karlsruhe Research Accelerator of KIT was applied to study the processes under realistic exhaust gas conditions. "Based on these observations of catalytic converter materials under real conditions, findings can be transferred much more quickly to application," Gänzler points out.

With the help of the findings obtained, catalytic activity of diesel oxidation catalytic converters can be enhanced at low temperature. From their observations, the scientists derived a promising basic concept to specifically adjust the size and structure of platinum particles as a function of the catalytic activity required during operation. The concept can be used among others to significantly improve catalytic performance after the cold start of combustion engines and when driving in urban traffic. "The structure of the noble metal nanoparticles can be influenced by short-term modifications of the engine operation mode, for instance," Gänzler says.

Based on the findings, current and future new types of catalytic converters can be improved and their economic efficiency can be increased, as the noble metal concentration can be reduced by up to 50%. The study that is considered "one of the big highlights in catalytic converter research" by Professor Jan-Dierk Grunwaldt of ITCP meets with big interest of experts. It was carried out in the course of the project "ORCA - Oxidation/Reduction Catalytic Converter for Diesel Vehicles of the Next Generation" that is part of the Deufrako German-French research collaboration. The project is funded with EUR 960,000 by the Federal Ministry for Economic Affairs and Energy. Apart from KIT, the Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON), TU Darmstadt, the Solvay company, and Umicore AG & Co. KG, a materials technology and recycling company in Hanau, take part in the collaboration project.

###

Andreas M. Gänzler, Maria Casapu, Philippe Vernoux, Stéphane Loridant, Francisco J. Cadete Santos Aires, Thierry Epicier, Benjamin Betz, Rüdiger Hoyer, and Jan-Dierk Grunwaldt: Tuning the Structure of Platinum Particles on Ceria In Situ for Enhancing the Catalytic Performance of Exhaust Gas Catalysts. DOI: 10.1002/anie.201707842

http://onlinelibrary.wiley.com/doi/10.1002/anie.201707842/abstract

More information:

http://www.itcp.kit.edu/abgaszentrum (in German only)

More about the KIT Mobility Systems Center http://www.kit.edu/research/6720.php

For further information, please contact:

Kosta Schinarakis, Science Scout, Phone: 49-721-608-41956, Fax: 49-721-608-43658, Email: schinarakis@kit.edu

Being "The Research University in the Helmholtz Association," KIT creates and imparts knowledge for the society and the environment. It is the objective to make significant contributions to the global challenges in the fields of energy, mobility and information. For this, about 9,300 employees cooperate in a broad range of disciplines in natural sciences, engineering sciences, economics, and the humanities and social sciences. KIT prepares its 26,000 students for responsible tasks in society, industry, and science by offering research-based study programs. Innovation efforts at KIT build a bridge between important scientific findings and their application for the benefit of society, economic prosperity, and the preservation of our natural basis of life.

Since 2010, the KIT has been certified as a family-friendly university.

This press release is available on the internet at http://www.sek.kit.edu/english/press_office.php.

Monika Landgraf | EurekAlert!

More articles from Life Sciences:

nachricht Turning carbon dioxide into liquid fuel
06.08.2020 | DOE/Argonne National Laboratory

nachricht Tellurium makes the difference
06.08.2020 | Friedrich-Schiller-Universität Jena

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: ScanCut project completed: laser cutting enables more intricate plug connector designs

Scientists at the Fraunhofer Institute for Laser Technology ILT have come up with a striking new addition to contact stamping technologies in the ERDF research project ScanCut. In collaboration with industry partners from North Rhine-Westphalia, the Aachen-based team of researchers developed a hybrid manufacturing process for the laser cutting of thin-walled metal strips. This new process makes it possible to fabricate even the tiniest details of contact parts in an eco-friendly, high-precision and efficient manner.

Plug connectors are tiny and, at first glance, unremarkable – yet modern vehicles would be unable to function without them. Several thousand plug connectors...

Im Focus: New Strategy Against Osteoporosis

An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.

Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...

Im Focus: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

Rare Earth Elements in Norwegian Fjords?

06.08.2020 | Earth Sciences

Anode material for safe batteries with a long cycle life

06.08.2020 | Power and Electrical Engineering

Turning carbon dioxide into liquid fuel

06.08.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>