Porous and Flexible Aramid Nanofiber/MXene Nanosheet Composite Aerogel for Rapid Ammonia Sensing at Room Temperature

Abstract

The industrialization process accelerates more and more kinds of volatile gas, with serious threats to the environment or human health having received great attention. Therefore, rapid real-time monitoring of harmful gases is urgently needed. This study investigated the gas-sensitive properties of an aramid nanofiber/MXene nanosheet (ANF/MXene) composite aerogel for detecting ammonia (NH₃) at room temperature. Initially, two-dimensional (2D) MXene nanosheets were synthesized by removing Al atoms from Ti₃AlC₂ (MAX phase), which were then combined with ANF to produce a porous composite aerogel through freeze-drying. At room temperature, the response value of the ANF/MXene aerogel to 50 ppm of NH₃ was approximately 4.96%, with a rapid recovery time (28 s), and remained stable even after 10 cycles. Additionally, the aerogel exhibited excellent long-term stability, lasting up to 45 days. Moreover, the ANF/MXene composite aerogel showed outstanding flexibility and flame retardancy, and it could bend and recover at low temperatures (−196 °C). As a result, the good gas-sensitive properties and stable mechanical properties enable the ANF/MXene aerogel to be suitable for flexible wearable sensor devices toward different environmental conditions in the future.