Highly sensitive and selective volatile organic amine (VOA) sensors using mesoporous WO 3 –SnO 2 nanohybrids

Considering the tremendous toxic effect on human well being and environment, the qualitative and quantitative determination of volatile organic amines (VOAs) is of significant importance. In this paper, nanostructures of WO3–SnO2 having large surface area and uniform pore channels were produced using mesoporous silica, SBA-15 as hard template using a nanocasting strategy. Sensors based on mesoporous WO3–SnO2 nanohybrids were fabricated for detection of important biological odor markers including triethylamine, ethylenediamine, ethanolamine, cyclohexylamine gases. The results exhibit that mesoporous WO3–SnO2 are highly sensitive and distinctly selective to triethylamine (TEA). The response (Ra/Rg) of this sensor to 50 ppm TEA was 87 with a fast response and recovery times of 6 and 7 s respectively at the operating temperature of 220 °C. The detection limit can also be as low as 1 ppm-level with a response of 3. Besides, the sensor shows excellent response/recovery and stability in the concentrations ranging from 1 to 500 ppm. These high sensing performances mainly attribute to the formation of unique heterojunction at the WO3–SnO2 interface and the presence of intrinsic high surface area supported by mesopores arrangement, which collectively offers great variation of resistance in air and TEA molecules (heterojunction) alongside facilitating the faster propagation and adsorption/desorption of TEA molecules across the sensor surface (mesoporous structure). Thus, the nanocasted mesoporous material provides an effective and efficient strategy to design new TEA gas sensors.