A comparison of NO2 sensing characteristics of α- and γ-iron oxide-based solid-state gas sensors

• Published in: Applied physics. A, Materials science & processing Vol. 126; no. 10
• Main Authors: Hjiri, M., Zahmouli, N., Khouzami, K., Mir, L. El, Aida, M. S., Moulaee, K., Lemine, O. M., Leonardi, S. G., Neri, G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2020; Springer Nature B.V
• Subjects: Applied physics; Characterization and Evaluation of Materials; Condensed Matter Physics; Ethanol; Gas sensors; Hematite; Iron oxides; Machines; Manufacturing; Materials science; Microstructure; Monitoring; Nanotechnology; Nitrogen dioxide; Optical and Electronic Materials; Physics; Physics and Astronomy; Processes; Sensors; Sol-gel processes; Solid state; Surfaces and Interfaces; Thin Films; Solid-state NO; sensor; α-fe; γ-fe; O
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-020-03829-3

In this work, we report on the successful synthesis of α- and γ-iron oxide (hematite and maghemite, respectively) nanopowders using a simple sol–gel technique followed by dries in supercritical ethanol. Microstructural and morphological characterizations were performed using X-ray diffraction (XRD) and transmission and scanning electron microscopies (TEM and SEM). The iron oxide semiconducting materials have been tested as sensing layer in solid-state conductometric planar sensors for the monitoring sof low NO
2
concentrations in air. This study demonstrated that the crystalline microstructure of the iron oxide nanopowders greatly affects the NO
2
sensing properties, allowing to tune the performances of the developed sensor towards the target gas. γ-Fe
2
O
3
nanopowder-based sensor resulted to have better performance than α-Fe
2
O
3
sensor for NO
2
monitoring.