A shows the catalytic foil in a relatively smooth state, image B shows a state with many folds.
Researchers at the Fritz-Haber Institute in Berlin have recently discovered chemical-thermal-mechanical oscillations that show, indirectly, the rate of certain reactions.
The pattern formation of a catalytic surface reaction is influenced by the temperature at which the reaction takes place. If the temperature of the surface is changed, then the course of the chemical processes changes as well. In extreme cases this change can lead to front formation, i.e. patterns, or, for example, to the overheating of the catalysts. Scientists in the research group led by Professors Harm Hinrich Rotermund and Gerhard Ertl at the Fritz-Haber Institute in Berlin have recently begun to study these processes.
In particular, they have investigated more precisely the influence of heat production during catalytic surface reactions between oxygen and carbon monoxide and pattern formations using an ultra-thin platinum catalyst. During the investigation it was established that, like a beating heart, the platinum foil began to pulsate mechanically during the reactions. With mathematical models and computer simulations the scientists were able to show that the elastic deformations of the foil were in fact due to the oscillation of the chemical reaction itself. This effect can now be used to precisely measure the amount of heat created during these chemical reactions (Science, 20 June, 2003).
Prof. Dr. Harm Hinrich Rotermund | EurekAlert!
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