Gas-Sensors for NO₂ Detection Based on Multi-Walled Carbon Nanomaterials and Their Mixtures

In this work, the sensing properties of pure multi-walled carbon nanotubes and their mixtures used as an active material for chemoresistive gas sensors were studied. Initial materials were analyzed by scanning electron spectroscopy, Raman spectroscopy, and X-ray diffraction. The surface area was measured by low-temperature nitrogen adsorption. The films of initial multi-walled carbon nanotubes and their mixtures taken in mass ratios of 15/85, 30/70, 50/50 have been obtained by drop casting. Textolite with copper contacts on the edges of one side was used as a substrate. Gas sensing properties (the response and the recovery time) were investigated to 100-500 ppm NO
2
at room temperature. The drop cast films of initials multi-walled carbon nanotubes and their mixtures as an active material showed high sensitivity and rapid recovery rate to nitrogen dioxide. It was found that mixtures of multi-walled carbon nanotubes have better sensing properties compared to pristine multi-walled carbon nanotubes.