A 3D α-MoO3 nanostructure for high-performance triethylamine (TEA) detection was synthesized via the facial oxidation of MoS2 nanoflowers (NFs) obtained by a hydrothermal process. The influence of the time of hydrothermal process in growing MoS2 on the morphologies of the final MoO3 obtained after calcination was investigated. As-obtained MoO3 and their precursors were systematically characterized by various techniques, such as X-ray diffraction, Raman, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and N2 adsorption-desorption isotherms. Results showed that MoO3 with a hierarchical layered nanostructure was successfully obtained. After hydrothermal treatment of the MoS2 precursor for 20 h, the typical MoO3-based sensor (called M20) exhibited a high response of 2.42 at a very low TEA concentration of only 0.1 ppm at 240 °C. The M20 sensor response to 50 ppm TEA was as high as 125 with a fast response/recovery time of 14/22 s. Moreover, the sensor had a high stability and reproducibility as well as a high selectivity against other interfering VOCs or gases. Due to the tendency of TEA to adsorb to active oxygen sites of MoO3, the enhanced sensing properties of MoO3 can be ascribed to the remarkable hierarchical structure and large surface area. MoO3 obtained after calcination of hydrothermally grown MoS2 is thus a promising sensing material for enhanced TEA gas detection.
Keywords: Calcination process; Gas sensing; Hydrothermal method; Layered MoO(3) hierarchical nanostructure; Triethylamine.
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