Heterostructured NiO/ZnO Nanorod Arrays with Significantly Enhanced H<sub>2</sub>S Sensing Performance
H<sub>2</sub>S gas sensors were fabricated using p-n heterojunctions of NiO/ZnO, in which the ZnO nanorod arrays were wrapped with NiO nanosheets via a hydrothermal synthesis method. When the H<sub>2</sub>S gas molecules were adsorbed and then oxidized on the ZnO surfaces, th...
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doaj-b7037c91da5d4e0f803ab2bcbf8603942020-11-25T00:42:43ZengMDPI AGNanomaterials2079-49912019-06-019690010.3390/nano9060900nano9060900Heterostructured NiO/ZnO Nanorod Arrays with Significantly Enhanced H<sub>2</sub>S Sensing PerformanceDongyi Ao0Zhijie Li1Yongqing Fu2Yongliang Tang3Shengnan Yan4Xiaotao Zu5School of Physical, University of Electronic Science and Technology of China, Chengdu 610054, ChinaSchool of Physical, University of Electronic Science and Technology of China, Chengdu 610054, ChinaFaculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, UKSchool of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, ChinaSchool of Physical, University of Electronic Science and Technology of China, Chengdu 610054, ChinaSchool of Physical, University of Electronic Science and Technology of China, Chengdu 610054, ChinaH<sub>2</sub>S gas sensors were fabricated using p-n heterojunctions of NiO/ZnO, in which the ZnO nanorod arrays were wrapped with NiO nanosheets via a hydrothermal synthesis method. When the H<sub>2</sub>S gas molecules were adsorbed and then oxidized on the ZnO surfaces, the free electrons were released. The increase in the electron concentration on the ZnO boosts the transport speed of the electrons on both sides of the NiO/ZnO p-n junction, which significantly improved the sensing performance and selectivity for H<sub>2</sub>S detection, if compared with sensors using the pure ZnO nanorod arrays. The response to 20 ppm of H<sub>2</sub>S was 21.3 at 160 °C for the heterostructured NiO/ZnO sensor, and the limit of detection was 0.1 ppm. We found that when the sensor was exposed to H<sub>2</sub>S at an operating temperature below 160 °C, the resistance of the sensor significantly decreased, indicating its n-type semiconductor nature, whereas when the operating temperature was above 160 °C, the resistance significantly increased, indicating its p-type semiconductor nature. The sensing mechanism of the NiO/ZnO heterostructured H<sub>2</sub>S gas sensor was discussed in detail.https://www.mdpi.com/2079-4991/9/6/900ZnOnanorodsNiOp-n junctionH<sub>2</sub>S gas sensor |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Dongyi Ao Zhijie Li Yongqing Fu Yongliang Tang Shengnan Yan Xiaotao Zu |
spellingShingle |
Dongyi Ao Zhijie Li Yongqing Fu Yongliang Tang Shengnan Yan Xiaotao Zu Heterostructured NiO/ZnO Nanorod Arrays with Significantly Enhanced H<sub>2</sub>S Sensing Performance Nanomaterials ZnO nanorods NiO p-n junction H<sub>2</sub>S gas sensor |
author_facet |
Dongyi Ao Zhijie Li Yongqing Fu Yongliang Tang Shengnan Yan Xiaotao Zu |
author_sort |
Dongyi Ao |
title |
Heterostructured NiO/ZnO Nanorod Arrays with Significantly Enhanced H<sub>2</sub>S Sensing Performance |
title_short |
Heterostructured NiO/ZnO Nanorod Arrays with Significantly Enhanced H<sub>2</sub>S Sensing Performance |
title_full |
Heterostructured NiO/ZnO Nanorod Arrays with Significantly Enhanced H<sub>2</sub>S Sensing Performance |
title_fullStr |
Heterostructured NiO/ZnO Nanorod Arrays with Significantly Enhanced H<sub>2</sub>S Sensing Performance |
title_full_unstemmed |
Heterostructured NiO/ZnO Nanorod Arrays with Significantly Enhanced H<sub>2</sub>S Sensing Performance |
title_sort |
heterostructured nio/zno nanorod arrays with significantly enhanced h<sub>2</sub>s sensing performance |
publisher |
MDPI AG |
series |
Nanomaterials |
issn |
2079-4991 |
publishDate |
2019-06-01 |
description |
H<sub>2</sub>S gas sensors were fabricated using p-n heterojunctions of NiO/ZnO, in which the ZnO nanorod arrays were wrapped with NiO nanosheets via a hydrothermal synthesis method. When the H<sub>2</sub>S gas molecules were adsorbed and then oxidized on the ZnO surfaces, the free electrons were released. The increase in the electron concentration on the ZnO boosts the transport speed of the electrons on both sides of the NiO/ZnO p-n junction, which significantly improved the sensing performance and selectivity for H<sub>2</sub>S detection, if compared with sensors using the pure ZnO nanorod arrays. The response to 20 ppm of H<sub>2</sub>S was 21.3 at 160 °C for the heterostructured NiO/ZnO sensor, and the limit of detection was 0.1 ppm. We found that when the sensor was exposed to H<sub>2</sub>S at an operating temperature below 160 °C, the resistance of the sensor significantly decreased, indicating its n-type semiconductor nature, whereas when the operating temperature was above 160 °C, the resistance significantly increased, indicating its p-type semiconductor nature. The sensing mechanism of the NiO/ZnO heterostructured H<sub>2</sub>S gas sensor was discussed in detail. |
topic |
ZnO nanorods NiO p-n junction H<sub>2</sub>S gas sensor |
url |
https://www.mdpi.com/2079-4991/9/6/900 |
work_keys_str_mv |
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1725280632996626432 |