MoSe2 nanoflakes based chemiresistive sensors for ppb-level hydrogen sulfide gas detection

[Display omitted] •MoSe2 Nanosheets were prepared by liquid phase exfoliation.•The nanosheets were used as sensing material in a chemiresistive hydrogen-sulfide gas sensor operated at 200℃.•Experimentally H2S concentration of 50 ppb was detected with excellent response and recovery time.•MoSe2 based...

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Bibliographic Details
Published in:Sensors and actuators. B, Chemical Vol. 297; p. 126687
Main Authors: Jha, Ravindra Kumar, D’Costa, Jostin Vinroy, Sakhuja, Neha, Bhat, Navakanta
Format: Journal Article
Language:English
Published: Lausanne Elsevier B.V 15-10-2019
Elsevier Science Ltd
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Summary:[Display omitted] •MoSe2 Nanosheets were prepared by liquid phase exfoliation.•The nanosheets were used as sensing material in a chemiresistive hydrogen-sulfide gas sensor operated at 200℃.•Experimentally H2S concentration of 50 ppb was detected with excellent response and recovery time.•MoSe2 based H2S sensors were found to be highly stable when operated in ambient.•A mechanism based on the experimental results was proposed. Detection and quantification of hydrogen sulfide (H2S) gas is important as it influences directly human health, our environment, and operations of several industries including food and beverages, oil, construction, and medicine. It also acts as biomarker in diagnosis of halitosis at early stage. We report herein liquid exfoliated MoSe2 nanoflakes based stable chemiresistive H2S gas sensor which operate at moderate temperature of 200℃. The response of p-type MoSe2 gas sensor device (when operated in ambient environment) was found to be varying between 15.87%–53.04% when the concentration of H2S was varied between 50 ppb – 5.45 ppm. The response of the device decreases when the measurements were done in synthetic air environment and it varies between 7.13%–19.87% for the concentration range of 500 ppb - 5.45 ppm. The response (%), recovery rate (%), hysteresis, experimental lowest detection limit etc. of the device suggest that the device performs better when operated in ambient than in synthetic air which suggest its real time device application. The response time and recovery time of the sensor are 15 s and 43 s respectively for 100 ppb of H2S. The sensor performance was found to be highly repeatable with sensitivity of 5.57%/ppm of H2S. The theoretical limit of detection and limit of quantization of the device were found to be 6.73 ppb and 22.44 ppb respectively. Based on chemical analysis, a plausible mechanism based on charge transfer phenomenon has been proposed for this sensor.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2019.126687