P2NG.8 - Formaldehyde Sensor Based on Flame-made AgOx-doped SnO2 Nanoparticulate Sensing Films

17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
Vienna, Austria
P-2 - Nanomaterials for Gas Sensing
K. Khamfoo - Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai (Thailand), A. Wisitsoraat, A. Tuantranont, S. Phanichphant, C. Liewhiran - Center of Advanced Materials for Printed Electronics and Sensors, Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai (Thailand)
859 - 860


Formaldehyde (HCHO) is one kind of the most volatile organic compounds (VOCs) that was widely used in household materials associated with many health risk factors and is identified as a major cause of sick building syndrome (SBS) [1, 2]. It is thus important to develop sensitive gas sensors capable of formaldehyde dection below its threshold limit value (TLVs) for health safety. In this work, flame-made 0-1 wt% AgOx-doped SnO2 nanoparticles were developed and characterized for detection of HCHO. The structural properties of as-prepared materials and their fabricated sensors were characterized by X-ray diffraction, Energy-dispersive X-ray spectroscopy, nitrogen adsorption, and electron microscopy. The results indicated that the AgOx-doped SnO2 nanoparticles ( 20 nm) had spheriodal morphology with highly crystalline tetragonal cassiterite SnO2 structure and AgOx may form a solid solution with SnO2 matrix. For gas sensing test, the gas sensing properties of the pure SnO2 and AgOx-doped SnO2 sensing film were systematically tested under exposure towards 50-200 ppm HCHO with different operating temperatures ranging from 150-400°C in dry air. From the sensing data, AgOx doping with an optimal Ag content of 0.2 wt% led to significant enhancement of HCHO response by more than one order of magnitude compared with undoped one. In particular, 0.2 wt% AgOx-doped SnO2 sensing film exhibited a high response of ~500 to 2000 ppm HCHO at 350°C. Therefore, the flame-spray-made 0.2 wt% AgOx-doped SnO2 sensor is one of the most promising candidate for sensitive HCHO detector and may be useful in environmental and SBS applications.