Selective NO2 sensor based on Bi2O3 branched SnO2 nanowires

•We presented a highly sensitive and selective NO2 sensor based on Bi2O3 branched SnO2 nanowires.•The sensor showed a high response (Rg/Ra) of 56.92 to 2 ppm of NO2 gas•The sensor demonstrated excellent selectivity towards NO2 gas.•We explored the sensing mechanisms, in regard to the selective sensi...

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Bibliographic Details
Published in:Sensors and actuators. B, Chemical Chemical, 2018-11, Vol.274, p.356-369
Main Authors: Bang, Jae Hoon, Choi, Myung Sik, Mirzaei, Ali, Kwon, Yong Jung, Kim, Sang Sub, Kim, Tae Whan, Kim, Hyoun Woo
Format: Article
Language:English
Subjects:
Bi2O3
Branched nanowire
Gas sensor
Selectivity
SnO2
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Summary:•We presented a highly sensitive and selective NO2 sensor based on Bi2O3 branched SnO2 nanowires.•The sensor showed a high response (Rg/Ra) of 56.92 to 2 ppm of NO2 gas•The sensor demonstrated excellent selectivity towards NO2 gas.•We explored the sensing mechanisms, in regard to the selective sensing to NO2 gas. We present a highly sensitive and selective NO2 sensor based on Bi2O3 branched SnO2 nanowires (NWs). SnO2 NWs were first synthesized by a vapor-liquid-solid method, were coated with an Au layer, and Bi2O3 branches were grown on their stems by the same procedure used for pure Bi powders. The fabricated sensor showed a high response (Rg/Ra) of 56.92 to 2 ppm of NO2 gas at an optimal temperature. Furthermore, its response to other interfering gases such as ethanol, acetone, toluene, and benzene, was less than 1.55, which demonstrated excellent selectivity of the sensor towards NO2 gas. For comparison and to better understand the sensing mechanism, a pristine SnO2 NWs sensor was also tested. The superior sensing properties of the branched NW sensor relative to the pristine sensor were mainly attributed to the high surface area of the sensor resulting from Bi2O3 branching, as well as the formation of homo-and heterojunctions (Bi2O3-SnO2). In addition, several factors including the presence of Au contributed to the excellent selectivity to NO2 gas. Based on the results obtained in this work, we believe that the present sensor with an easy fabrication method, along with its high sensitivity and selectivity towards NO2, can be used for the detection of NO2 gas in real applications.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2018.07.158