Scientists in the UK have explained the involvement of electrons in the reduction of ceria-coated precious metal catalysts used in catalytic converters.

Paul Collier and colleagues at Johnson Matthey Technology Centre and the University of Oxford, have shown it is possible to reverse the metal-support relationship.

Looking at precious-metal particles in ceria, Collier was able to control the way the metal oxide gives up its oxygen to a reactant gas, showing a dependence on a fundamental property in the metal.

Known as the work function, the property measures the ease of electron transfer to and from the metal.

This means that the better the metal is at accepting electrons, the faster the ceria releases its oxygen.

Speaking to ChemComm, Collier said: "'This is exciting because previously people had exclusively thought that precious metals function in an indirect chemical way by activating gas phase chemical reducing agents that subsequently help ceria to give up its oxygen.

"Now we know that there is another way that precious metals can encourage ceria to give up its oxygen and that is a direct electronic one," he added.

As a result, it is hoped that scientists will be able to improve the performance of ceria redox catalysts.

Source:

Hot article: Understanding catalytic converters, 03/03/08
http://www.rsc.org/Publishing/Journals/cc/News/B718956G_Collier.asp

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