Porous α-Fe2O3 gas sensor with instantaneous attenuated response toward triethylamine and its reaction kinetics

Abstract To achieve highly selective and rapid detection of triethylamine (TEA) at a relatively low temperature remains challenging. In this work, we report an ultrasensitive TEA gas sensor with a specific response based on the porous α-Fe2O3 hollow sphere array, which shell is composed of fusiform particles. At a low operating temperature (160 °C), the sensor shows high response (75.8) toward 10 ppm TEA with a short response time (2 s) and can detect TEA as low as 50 ppb. More importantly, an obvious attenuation characteristic is observed during TEA detection. This distinctive response toward TEA gas is repeatable when the operating temperature is over a threshold (>120 °C). Moreover, the instantaneous attenuated response is found to be independent of the gas concentration and humidity but much related to specific gases, demonstrating its potential to be used as a characteristic signal to achieve highly selective detection of TEA molecules. Furthermore, based on density functional theory (DFT) calculations, the attenuated response can be ascribed to a special surface dynamic reaction process involving the thermal decomposition of TEA molecules and the formation of nitrogen oxides, which is verified by the quasi in-situ X-ray photoelectron spectroscopy analysis. This work will provide a new idea for developing highly selective and sensitive sensors.