CARBON NANOTUBE BASED AMMONIA SENSOR - Isis Project No 2861

Introduction

Isis Innovation, the technology transfer company of the University of Oxford, releases a new method for sensing ammonia aimed at industrial applications.

Marketing Opportunity

Ammonia (NH3) is a noxious and toxic gas. Determination of NH3 concentration is important in monitoring industrial processes and also in the water industry for ensuring that effluent meets regulations.  Semi-conductor based sensors are widely used, but are known to become less effective over time.  Electrochemical sensors have also been used, however such systems have experienced premature failure from analyte or solvent intercalation of the graphite-based electrodes.   Clearly a more robust electrochemical sensor, capable of accurate measurement of NH3 concentration in industrial environments, would be highly desirable.

The Oxford Invention

A multiwalled carbon-nanotube (MWCNT)-based ammonia sensing method has been developed by scientists at Oxford University.  Figure A shows how intercalation can lead to exfoliation of graphite, whilst Figure B shows the how intercalation does not occur with bamboo MWCNTs; hence electron transfer occurs at edge plane sites.  X-Ray diffraction measurements (Figure C) over time further show that the bamboo MWCNT structure is not affected by intercalation.   Experimental results show that MWCNTs provide excellent quantitative voltammetric response to the oxidation of NH3 allowing useful electrochemical measurements to be made.

Commercialisation Status

The technology is the subject of an International Patent Application. Isis would like to talk to companies interested in developing

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