PANI/Ti3C2Tx composite nanofiber-based flexible conductometric sensor for the detection of NH3 at room temperature

The rational design of sensing materials with distinct morphologies and compositions is important to construct outstanding flexible gas sensors. Herein, a mesh polyaniline (PANI)/Ti3C2Tx composite nanofiber-based flexible sensor was constructed by electrospinning of PANI and few-layer Ti3C2Tx nanosheets. Sensing results indicated that this novel PANI/Ti3C2Tx flexible sensor demonstrated much higher NH3 sensing response (2.3-fold improvement @ 20 ppm) in comparison with the sensor based on pure PANI nanofibers at 25 °C. Under different bending angles (maximum compression of 150°) and different bending times (maximum bending of 3200 times), the PANI/Ti3C2Tx flexible sensor maintained steady sensing behavior towards 20 ppm NH3, which reflected its good flexible bending stability. The PANI/Ti3C2Tx flexible sensor also exhibited good selectivity, repeatability, as well as good long-term stability. The improvement of NH3 sensing properties can be ascribed to the formation of Schottky junctions between PANI and Ti3C2Tx nanosheets, improved protonation degree of PANI, and the special three-dimensional mesh fiber structure. Our work revealed that the PANI/Ti3C2Tx composite nanofibers with interconnected mesh fiber structure have great potential to construct flexible NH3 sensors.