In situ derived MOF/MXene-based SnO2/TiO2 heterostructures for ultrasensitive triethylamine sensing

Triethylamine (TEA) is a highly toxic and flammable volatile organic compound (VOC) that poses serious risks to both human health and environmental safety. Thus, the development of highly sensitive gas sensors for its trace-level detection is of pressing importance. In this work, SnO 2 /TiO 2 heterostructures were synthesized via an in-situ thermal transformation of Sn-MOF/MXene precursors. The derived materials benefit from the inherent high porosity and large specific surface area of MOF-based frameworks, as well as the tightly coupled heterointerface formed under the modulation of MXene, efficiently facilitating charge separation and transport, while TEA interacts more readily with active sites due to the richness of surface defects, thereby greatly boosting TEA adsorption and sensing response. The optimized MST-2 sensor exhibits an ultrahigh response of 3525.2 to 10 ppm TEA at a notably low operating temperature of 61 °C, along with excellent selectivity and good stability. Even at an ultralow TEA concentration of 10 ppb, the sensor maintains a strong response of 44.6. Furthermore, the adsorption characteristics of individual phases, interfacial charge transfer processes, and TEA adsorption enhanced mechanisms were systematically examined through density functional theory (DFT) calculations. The effective MOF/MXene-derived co-construction strategy offers a promising avenue for designing advanced TEA sensing materials.