Ti ₃ C ₂ T x Supported Cu ₃ (HHTP) ₂ Nanorod Arrays for High-Performance Hydrazine Hydrate Detection

Two-dimensional conductive metal–organic frameworks (2D- c MOFs) hold significant potential for gas-sensing applications, but their aggregation issues prevent high gas-sensing performance at room temperature (RT). To overcome this bottleneck, a Ti 3 C 2 T x nanosheet was used to in situ support Cu 3 (HHTP) 2 nanorod arrays to build a Cu 3 (HHTP) 2 /Ti 3 C 2 T x heterostructure, in which the introduced Ti 3 C 2 T x nanosheet not only promotes oriented growth of Cu 3 (HHTP) 2 nanorod arrays but also facilitates interfacial charge transfer. Consequently, the active surface exposure of Cu 3 (HHTP) 2 nanorods and gas diffusion pathways are maximized, further enhancing the detection performance toward hydrazine hydrate (N 2 H 4 ) gas. Gas-sensing tests reveal that a response time is only 2.3 min to 20 ppm of N 2 H 4 gas, and the actual lowest detectable concentration is down to 1 ppm at RT. Under 200 ppm of N 2 H 4 gas exposure, its response value reaches approximately seven times that of the original Cu 3 (HHTP) 2 sensor. The sensing mechanism of the Cu 3 (HHTP) 2 /Ti 3 C 2 T x heterostructure toward N 2 H 4 gas was elucidated through electrochemical impedance spectroscopy (EIS) data, in conjunction with density functional theory (DFT) calculations. This work presents a promising strategy for the heteroepitaxial growth of c -MOF nanorod arrays and paves the way for their application in the sensing of N 2 H 4 .