New property of flames sparks advances in technology

Jun 07, 2012

Chemists at UCL have discovered a new property of flames, which allows them to control reactions at a solid surface in a flame and opens up a whole new field of chemical innovation.

Published in the journal , authors of the new study have discovered their previous understanding of how flames interact with a solid surface was mistaken. For the first time, they have demonstrated that a particular type of chemistry, called redox chemistry, can be accurately controlled at the surface.

This finding has wide implications for future technology, for example in detection of chemicals in the air, and in developing our understanding of the chemistry of lightning. It also opens up the possibility of being able to perform nitrogen oxide and carbon dioxide electrolysis at the source for the management of green house gases.

Results of the study show that depending on the chemical make-up of the flame, scientists can record a distinctive electrical fingerprint. The fingerprint is a consequence of the behaviour of specific at the surface of a solid conducting surface, where electrons can exchange at a very precise voltage.

Dr Daren Caruana, from the UCL Department of Chemistry, said: "Flames can be modelled to allow us to construct efficient burners and . But the presence of charged species or ions and electrons in flames gives them a unique ."

Dr Caruana added: "By considering the gaseous flame plasma as an electrolyte, we show that it is possible to control redox reactions at the solid/gas interface."

The team developed an electrode system which can be used to probe the chemical make-up of flames. By adding chemical species to the flame they were able to pick up current signals at specific voltages giving a unique electrochemical finger print, called a voltammogram.

The voltammograms for three different - , molybdenum oxide and - are all unique. Furthermore, the team also demonstrated that the size of the current signatures depend on the amount of the oxide in the flame. Whilst this is possible and routinely done in liquids, this is the first time to be shown in the gas phase.

UCL chemists have shown that there are significant differences between solid/gas reactions and their liquid phase equivalents. Liquid free electrochemistry presents access to a vast number of redox reactions, current voltage signatures that lie outside potential limits defined by the liquid.

The prospect of new redox chemistries will enable new technological applications such as electrodeposition, electroanalysis and electrolysis, which will have significant economic and environmental benefits.

Dr Caruana said: "The mystique surrounding the properties of fire has always captivated our imagination. However, there are still some very significant technical and scientific questions that remain regarding fire and flame. "

Explore further: Team pioneers strategy for creating new materials

More information: 'Dynamic electrochemistry in flame plasma electrolyte' is published online in the journal Angewandte Chemie.

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tadchem
5 / 5 (2) Jun 07, 2012
IIRC, there was a gadget reported in the '60s in which the audio output of a radio/phonograph was fed through a small Tesla coil to boost the voltage and then fed capacitively into an open flame. The flame acted as an electrical-to-sound transducer, with current variations converted into pressure variations, which it could only manage if the flame itself was an electrical conductor
Shelgeyr
not rated yet Jun 07, 2012
Dr Caruana added: "By considering the gaseous flame plasma as an electrolyte, we show that it is possible to control redox reactions at the solid/gas interface."


Plasmas are such cool, wonderful things (well, not literally "cool" usually, but, you know, figure of speech) about which we keep learning ever more and more.

I think the only thing that surpasses my amazement with plasmas themselves is my amazement over the broad range of things that so many "scientists" claim (in ignorance) that they can NOT do. But that's a long fight for another thread (or actually many of them).

Good work, Dr Caruana!