Room Temperature Formaldehyde Sensing of Hollow SnO2/ZnO Heterojunctions Under UV-LED Activation

The room temperature gas sensing properties of the hollow SnO 2 /ZnO heterojunction-based chemiresistive sensors under ultraviolet {\left ({UV}\right)} radiation were investigated. The hollow SnO 2 /ZnO heterojunctions were fabricated using the template-assisted process followed with a hydrotherma...

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Bibliographic Details
Published in:IEEE sensors journal 2019-09, Vol.19 (17), p.7207-7214
Main Authors: Zhao, Lijia, Chen, Yupeng, Li, Xinyu, Li, Xiaogan, Lin, Shiwei, Li, Tie, Rumyantseva, Marina N., Gaskov, Alexander M.
Format: Article
Language:English
Subjects:
Catalytic converters
Ethanol
Formaldehyde
Gas detectors
Gas sensors
Heterojunctions
hollow SnO₂/ZnO heterojunctions
Hydrothermal treatment
II-VI semiconductor materials
Light emitting diodes
Microspheres
Organic chemistry
Oxidation
Room temperature
Room-temperature gas sensors
Selectivity
Sensitivity enhancement
Sensors
Surface morphology
Temperature sensors
Tin dioxide
Toluene
Ultraviolet radiation
UV activation
Zinc oxide
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Summary:The room temperature gas sensing properties of the hollow SnO 2 /ZnO heterojunction-based chemiresistive sensors under ultraviolet {\left ({UV}\right)} radiation were investigated. The hollow SnO 2 /ZnO heterojunctions were fabricated using the template-assisted process followed with a hydrothermal treatment. The sensor using this core-shell SnO 2 /ZnO heterojunctions showed a much higher response to formaldehyde under UV illumination compared to that without UV. Moreover, the response of this hollow heterojunctions-based sensor to formaldehyde is higher than the respective pure SnO 2 and ZnO hollow microspheres-based sensors under same conditions indicating the synthetic effect of the formed heterojunctions on the enhanced sensitivity. More strikingly, the response of the SnO 2 /ZnO heterojunctions-based sensors showed a much smaller response to ethanol, methanol, and toluene indicating an excellent selectivity whereas there is a large influence from ethanol if the sensor worked under the conventional heating method. It could be attributed to the lower oxidizing ability of the adsorbed, ionized oxygen with a negative monovalence on the oxide surface and thus a selective photo-catalytic conversion of formaldehyde over the other possible interferents. The long-term stability of the sensor operated under UV light was also studied.
ISSN:1530-437X
1558-1748
DOI:10.1109/JSEN.2019.2916879