Coaxial electrospinning In2O3/TiO2 core-shell nanofibers for enhanced triethylamine sensing

Triethylamine (TEA), a hazardous and flammable compound, poses significant risks to both human health and the environment. Therefore, the development of precise and rapid methods for detecting TEA in complex environments is imperative. In this study, In₂O₃/TiO₂ core-shell nanofibers (NFs) with different mass ratio were successfully obtained by coaxial electrospinning. Through the characterization and performance comparison of different ratio for [Ti]: [In] (1:2, 1:1, 2:1 and 3:1), it was found that the TEA sensor based on Ti₂In₁ owned the best sensing performance. Specifically, it demonstrated the highest response value of 250.8 to 200 ppm TEA at 280℃, the shortest response/recovery time (14/21 s) and the smallest stability fluctuation deviation (5.1%). Notably, the sensor exhibited excellent selectivity and anti-interference capability by distinguishing TEA from similar gases such as trimethylamine, dimethylamine, and ammonia. Compared with pristine TiO₂ and In₂O₃ nanofibers, the superior performance of the Ti₂In₁ sensor can be attributed to its unique core (In₂O₃)-shell (TiO₂) nanofiber architecture and the interfacial electron transfer processes occurring between these components, which were confirmed through ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) tests. Furthermore, electrochemical impedance spectra (EIS) and Mott-Schottky (MS) Nyquist measurement confirmed the sensor's excellent electron migration properties. These factors facilitated the adsorption, transport, and reaction of gas molecules, thereby in the enhancement of the TEA sensing performance. Moreover, density functional theory (DFT) calculation was executed and the same results as the experiment were obtained. This study paves the way for novel explorations into morphological manipulation and intrinsic mechanisms underlying TEA sensing materials.