P2NG.5 - Selective H2S Gas Sensors Based on Au-functionalized WO3 Nanowires

17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
Vienna, Austria
P-2 - Nanomaterials for Gas Sensing
M. Punginsang, C. Liewhiran - Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai (Thailand), A. Wisitsoraat - Carbon-based Devices and Nanoelectronics Laboratory, National Electronics and Computer Technology Center, National Science and Technology Development Agency, Klong Luang, Pathumthani (Thailand), S. Phanichphant - Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai (Thailand), D. Zappa, E. Comini, G. Sberveglieri - SENSOR Laboratory, University of Brescia, Brescia (Italy), A. Ponzoni - National Institute of Optics (INO) , National Research Council of Italy (CNR), Brescia (Italy)
853 - 854


Thermal oxidation is the one of techniques for synthesis of various one-dimensional metal oxide nanostructures which has been established by SENSOR laboratory [1-3]. Due to many advantages of this technique, including scalability for mass-production, capability to control the growth pattern with shadow masking technique and low cost method [1, 3], it is interesting to synthesize metal oxide nanowires by this method for gas sensing materials. In this present study, the fabricated sensor on WO3 nanowires sensing films were grown by thermal oxidation method on the alumina substrates in single step and then subsequently functionalized with gold nanoparticles as an excellent catalyst for gas-sensing reaction by RF magnetron sputtering with different sputtering time of 2, 5, 10 and 15 seconds. Structural characterizations of sensing films by electron microscopy and X-ray analysis revealed that WO3 nanowires were highly crystalline with monoclinic structure and metallic Aufunctionalized with crystalline WO3 nanowires. The effect of Au sputtering time on gas sensing properties of WO3 sensors were systematically tested towards H2S, CO, NO2 and acetone with different working temperatures ranging from 250-400ºC 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 comparing with the other gases. Particularly, the optimal Au-functionalized WO3 sensing film exhibited the highest response of 219 to 5 ppm H2S at the optimal working temperature of 350°C with relative humidity of 50%. Therefore, the excellent Au-functionalized WO3 nanowires are highly potential for selective H2S detection.