Engineering α-MoO3/TiO2 heterostructures derived from MOFs/MXene hybrids for high-performance triethylamine sensor

Triethylamine (TEA), a flammable and volatile toxic gas, poses significant risks to human health and the ecological environment. To rapidly detect TEA leakage in the environment and accurately determine its concentration, MoO3/TiO2-X (MMT-X) composites were synthesized using a simple condensation reflux and calcination. In this process, the exfoliated-Ti3C2Tx derived TiO2 were successfully assembled onto rod-shaped MoO3 derived from Mo-MOF. The abundance of surface defects and porous structure in the MMT-X composites promote interaction between TEA and active sites. Additionally, the constructed MoO3/TiO2 heterostructures offer rapid charge carrier transport pathways and sharp resistance changes. The optimal MMT-2 composite exhibited exceptional sensitivity (R = 566.7) towards 100 ppm TEA, displaying remarkable linearity, swift response/recovery times, outstanding selectivity, repeatability, and stability. Furthermore, density functional theory (DFT) calculations were employed to comprehend adsorption energies and the electronic structures at the atomic scale, elucidating the intrinsic correlation between TEA adsorption behavior and MoO3 (0 1 0) surface oxygen vacancies conversion, the properties of oxygen vacancies-induced gap states for facilitating electron transfer, and the sensitization mechanism of MoO3/TiO2 heterostructures. These findings provide novel insights for designing high-performance TEA gas sensors and theoretical guidance for TEA sensing mechanism.