Humidity independent hydrogen sulfide sensing response achieved with monolayer film of CuO nanosheets

•Humidity independent H2S detection is achieved with adsorbent-free CuO sensor.•Resistive Cu2S forms on CuO in wet condition, offsetting the drop of adsorbed oxygen.•Monolayer film structure is a key factor for achieving humidity independent response.•The sensor is sensitive and selective to H2S, an...

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Bibliographic Details
Published inSensors and actuators. B, Chemical Vol. 309; p. 127785
Main Authors Miao, Jiansong, Chen, Chuan, Lin, Jerry Y.S.
Format Journal Article
LanguageEnglish
Published Lausanne Elsevier B.V 15.04.2020
Elsevier Science Ltd
Subjects
Chemisorption
Copper oxides
CuO nanosheet
Detection
Environmental monitoring
Gas sensors
Humidity
Humidity independent
Hydrogen sulfide
Hydroxyl groups
Interference
Metal oxides
Monolayer
Monolayers
Nanosheets
Photoelectrons
Selectivity
Sensing mechanism
Surface reactions
Water vapor
Hydrogen sulfide
Monolayer
Humidity independent
CuO nanosheet
Sensing mechanism
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Summary:•Humidity independent H2S detection is achieved with adsorbent-free CuO sensor.•Resistive Cu2S forms on CuO in wet condition, offsetting the drop of adsorbed oxygen.•Monolayer film structure is a key factor for achieving humidity independent response.•The sensor is sensitive and selective to H2S, and stable in dry and wet conditions. Detection of ppm and sub-ppm level airborne hydrogen sulfide (H2S) is critical to both environmental monitoring and medical diagnosis. However, conductometric gas sensors based on semiconducting metal oxides are usually susceptible to humidity interference, which limits their performance in those applications. Typically, the hydroxyl groups formed by the chemisorption of water vapor on the surfaces of metal oxides prevent any further redox reaction, and in turn, passivate the sensing material. Departing from the traditional strategy of alleviating humidity interference with moisture adsorbents, we propose to explore the possible surface reactions between H2S and hydroxyl groups on the surface of copper (II) oxide (CuO) in this work. With a monolayer film of CuO nanosheets, we observe an unprecedented humidity independent H2S sensing performance. In addition, the sensor also shows excellent sensitivity and selectivity to H2S and high stability in dry and wet conditions. The mechanism underlying the stable sensing response regardless of humidity variations is investigated with X-ray photoelectron spectroscopy.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2020.127785