Scientific Results

Selective H2S gas sensors based on ohmic hetero-interface of Au-functionalized WO3 nanowires

Year: 2022

Authors: Punginsang M., Zappa D., Comini E., Wisitsoraat A., Sberveglieri G., Ponzoni A., Liewhiran C.

Autors Affiliation: -Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
-Center of Excellence in Materials Science and Technology, Chiang Mai University, Chiang Mai 50200, Thailand
-Sensor Laboratory, Department of Information Engineering, University of Brescia, Via Valotti 9, 25133, Brescia, Italy
-National Security and Dual-Use Technology Center, National Science and Technology Development Agency (NSTDA), Klong Luang, Phathum Thani 12120, Thailand
-National Institute of Optics of the National Research Council (CNR-INO), Unit of Brescia, Brescia 25123, Italy

Abstract: In this present study, the fabricated sensors based on WO3 nanowires sensing films were grown by thermal oxidation method on the alumina substrates in single step and subsequently functionalized with gold nano- particles, an excellent catalyst for gas-sensing reactions, by RF magnetron sputtering with different sputtering time of 2, 5, 10 and 15 s. Structural characterizations of sensing films by electron microscopy and X-ray analysis revealed that 5–15 nm Au nanoparticles with a single metallic state decorated the highly crystalline 20–30 nm WO3 nanowires with a monoclinic structure. The effect of Au sputtering time on gas sensing properties of WO3 sensors was systematically tested towards H2S, CO, NO2 and acetone, with different working temperatures ranging from 250 to 400 ◦C in dry air and humidity effects. It was found that an optimal Au sputtering time of 10 s led to significant enhancement of H2S-sensing performances compared with other tested gases. Particularly, the optimal Au-functionalized WO3 sensing film exhibited the highest response of 219 to 5 ppm H2S with the detection limit of 0.17 ppb at the optimal working temperature of 350 degC and a relative humidity of 50% (@20 degC). Therefore, the Au-functionalized WO3 nanowires are highly potential for selective H2S detection.

Journal/Review: APPLIED SURFACE SCIENCE

Volume: 571      Pages from: 151262-1  to: 151262-11

KeyWords: WO3; Nanowires; Thermal oxidation; Gold; Gas sensors
DOI: 10.1016/j.apsusc.2021.151262

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