Modulation of potential barrier heights in Co3O4/SnO2 heterojunctions for highly H2-selective sensors

[Display omitted] •The H2 sensing properties of p-Co3O4/n-SnO2 composites with different molar ratio of Co/Sn were systematically investigated.•The sensors demonstrate exclusive H2 sensing properties, which show an n-type sensing response to the typical reducing gases such as CO, H2S and NH3, but a...

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Bibliographic Details
Published inSensors and actuators. B, Chemical Vol. 244; pp. 694 - 700
Main Authors Huo, Lianping, Yang, Xi, Liu, Zengwei, Tian, Xin, Qi, Tianjiao, Wang, Xinfeng, Yu, Kun, Sun, Jie, Fan, Meikun
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.06.2017
Subjects
Co3O4/SnO2
Gas sensor
Heterojunction
Potential barrier
Selectivity
Potential barrier
Gas sensor
H2
Selectivity
Co3O4/SnO2
Heterojunction
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Summary:[Display omitted] •The H2 sensing properties of p-Co3O4/n-SnO2 composites with different molar ratio of Co/Sn were systematically investigated.•The sensors demonstrate exclusive H2 sensing properties, which show an n-type sensing response to the typical reducing gases such as CO, H2S and NH3, but a p-type towards H2.•The abnormal sensing behaviors might be associated with the modulation of potential barrier heights through the asymmetric gas sensing reactivity of heteromaterials. Chemiresistive gas sensors employing p-n heterostructures offer a compelling combination of high sensitivity and specific selectivity due to the synergic effects at interface. In this study, the p-Co3O4/n-SnO2 composites with different molar ratio of Co/Sn have been prepared using a simple soak-calcination method and their sensing properties are systematically investigated. The sensors demonstrate exclusive H2 sensing properties with p-type sensing response, and n-type sensing response to the typical reducing gases such as CO, H2S and NH3. We propose that the abnormal sensing behaviors might be associated with the modulation of potential barrier heights formed in p-Co3O4/n-SnO2 heterojunctions, namely the modulation from the asymmetric gas sensing reactivity of SnO2 and Co3O4 to the reducing gases. This work may open up a general approach for tailoring the sensing selectivity of gas sensors via the modulation of potential barrier heights in p-n heterojunctions.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2017.01.061