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NO₂ Selective Sensor Based on α-Fe₂O₃ Nanoparticles Synthesized via Hydrothermal Technique.

Mokhtar HjiriMohamed Salah AidaGiovanni Neri
Published in: Sensors (Basel, Switzerland) (2019)
In the present work, hematite (α-Fe₂O₃) nanopowders were successfully prepared via a hydrothermal route. The morphology and microstructure of the synthesized nanopowders were analyzed by using scanning and transmission electron microscopy (SEM and TEM, respectively) analysis and X-ray diffraction. Gas sensing devices were fabricated by printing α-Fe₂O₃ nanopowders on alumina substrates provided with an interdigitated platinum electrode. To determine the sensor sensitivity toward NO₂, one of the main environmental pollutants, tests with low concentrations of NO₂ in air were carried out. The results of sensing tests performed at the operating temperature of 200 °C have shown that the α-Fe₂O₃ sensor exhibits p-type semiconductor behavior and high sensitivity. Further, the dynamics exhibited by the sensor are also very fast. Lastly, to determine the selectivity of the α-Fe₂O₃ sensor, it was tested toward different gases. The sensor displayed large selectivity to nitrogen dioxide, which can be attributed to larger affinity towards NO₂ in comparison to other pollutant gases present in the environment, such as CO and CO₂.
Keyphrases
  • electron microscopy
  • high resolution
  • magnetic resonance imaging
  • computed tomography
  • mass spectrometry
  • structural basis