Controlling the Cross-Sensitivity of Carbon Nanotube-Based Gas Sensors to Water Using Zeolites.
Carbon nanotube-based gas sensors can be used to detect harmful environmental pollutants such as NO2at room temperature. Although they show promise as low-powered, sensitive, and affordable monitoring devices, cross-sensitivity of functionalized carbon nanotubes to water vapor often obscures the detection of target molecules. This is a barrier to adoption for monitoring of airborne pollutants because of the varying humidity levels found in real world environments. Zeolites, also known as molecular sieves because of their selective adsorption properties, are used in this work to control the cross-sensitivity of single-walled carbon nanotube (SWCNT)-based sensors to water vapor. Zeolites incorporated into the sensing layer are found to reduce interference effects that would otherwise obscure the identification of NO2gas, permitting repeatable detection over a range of relative humidities. This significant improvement is found to depend on the arrangement of the SWCNT-zeolite layers in the sensing device, as well as the hydrophilicity of the chosen zeolite.
Department of Security and Crime Science, University College London , 35 Tavistock Square, London WC1H 9EZ, United Kingdom.
Gwyn P
GP
Evans
Department of Chemistry, University College London , 20 Gordon Street, London WC1H 0AJ, United Kingdom.
David J
DJ
Buckley
Department of Chemistry, University College London , 20 Gordon Street, London WC1H 0AJ, United Kingdom.
Abdul-Lateef
AL
Adedigba
Department of Chemistry, University College London , 20 Gordon Street, London WC1H 0AJ, United Kingdom.
Gopinathan
G
Sankar
Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, United Kingdom.|London Centre for Nanotechnology , 17-19 Gordon Street, London WC1H 0AH, United Kingdom.
Neal T
NT
Skipper
Department of Chemistry, University College London , 20 Gordon Street, London WC1H 0AJ, United Kingdom.
Ivan P
IP
Parkin
environmental monitoring; gas sensor; humidity; molecular sieve; nanotube network; nitrogen dioxide; single-walled carbon nanotubes; zeolite