Ti₃C₂T_x MXene-Derived Metal–Organic Frameworks for Room Temperature NO₂ Detection

This work reports a new method toward creating two-dimensional (2D) conductive metal–organic frameworks (MOFs) for enhanced gas sensing applications. By employing Ti 3 C 2 T x MXene as a metal precursor and 2-aminoterapthalic acid as an organic linker, MXene-derived MOFs with high surface reactivity were synthesized. The Ti 3 C 2 T x MXene sensor, initially selective toward NH 3 gas, was tailored to detect NO 2 gas by integrating it with MXene-derived MOFs, which offer abundant active sites on the surface. The resulting MOF sensor exhibited a notable sensing response of 76.52%, with rapid response and recovery times of 31.5 and 80.2 s, respectively, at room temperature and 35% relative humidity (RH). The sensor’s specificity toward acidic NO 2 gas was attributed to the acid–base interaction facilitated by the organic linker, inducing detectable changes in resistance. Additionally, the fabricated MOF sensor demonstrated excellent repeatability and stability under ambient conditions. Remarkably, the sensor exhibited a low detection limit (LOD) of 5 ppb for NO 2 gas. These findings underscore the potential of utilizing 2D MOF sheets derived from MXene precursors for practical gas sensing applications, highlighting their versatility and effectiveness.