MXene/MoS2 nanosheet/polypyrrole for high-sensitivity detection of ammonia gas at room temperature

MXenes have recently emerged as innovative 2D materials with potential for gas-sensing applications. In this study, we produced a polypyrrole (PPy)-coated MXene/MoS2 nanocomposite-based gas sensor for ammonia detection at room temperature. MXene-loaded MoS2 nanocomposites with loose heterogeneous architectures were produced via a one-step hydrothermal technique based on an electrostatically ordered self-assembly. An etched MXene surface with evenly wrapped MoS2 nanosheets created a highly synergistic metal–semiconductor-like contact, producing an anti-blocking layer that had a trapping effect on electrons produced via NH3 sensing. PPy was polymerized in situ on the surface of the MXene/MoS2 composite, producing a self-supporting structure. The MXene/MoS2/PPy nanocomposite-based sensor exhibited response values approximately five times greater than sensors based on pure MXene when exposed to 100 ppm of ammonia at room temperature. Furthermore, the sensor could detect ammonia at concentrations as low as 10 ppm and presented a response of 2.08 at room temperature. The MXene/MoS2/PPy nanocomposite-based sensor also demonstrated long-term stability, high response and recovery rates, good humidity tolerance, and high selectivity for ammonia.