An impedimetric ammonia sensor based on nanostructured alpha -Fe sub(2)O sub(3)

An impedimetric sensor has been developed for the detection of ammonia vapour using a highly crystalline alpha -Fe sub(2)O sub(3) synthesized by a solution combustion method. The as-prepared alpha -Fe sub(2)O sub(3) requires annealing at 600 degree C for 2 h to obtain high crystallinity and good pur...

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Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2013-12, Vol.2 (2), p.394-401
Main Authors: Karthick Kannan, Padmanathan, Saraswathi, Ramiah
Format: Article
Language:English
Subjects:
Ammonia
Combustion
Ethyl alcohol
Methyl alcohol
Nanostructure
Sensors
Sustainability
Vapour
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Summary:An impedimetric sensor has been developed for the detection of ammonia vapour using a highly crystalline alpha -Fe sub(2)O sub(3) synthesized by a solution combustion method. The as-prepared alpha -Fe sub(2)O sub(3) requires annealing at 600 degree C for 2 h to obtain high crystallinity and good purity. The material is characterized by XRD, FT-IR, SEM and AFM. AC impedance data reveal a systematic variation in charge transfer resistance with respect to ammonia concentration. A linear calibration between sensitivity and ammonia concentration is obtained in the concentration range from 100 to 1000 ppm. The sensor has a sensitivity (%) of about 33 with a response and recovery time of 40 and 50 s, respectively, at 100 ppm of ammonia. The sensor can be described by an equivalent circuit having two resistance and two capacitance components parallel to each other. alpha -Fe sub(2)O sub(3) is found to show a higher sensitivity to ammonia in comparison to other vapours like acetone, methanol, ethanol, propanol and butanol.
ISSN:2050-7488
2050-7496
DOI:10.1039/c3ta13553e