Integrated Temperature–NH3 Multiplex Sensing Fibers Enabled by Programmable Assembly of MXene@MoS2 Heterojunction and p/n-Type Thermoelectric Core for Firefighting Clothing

Firefighting clothing provides essential safeguards for firefighters while engaging in fire suppression and life rescue operations. However, the inability to actively detect hazardous gas and self-thermal degradation of conventional firefighting clothing induce critical safety threats to firefighters. Herein, we design a dual-mode perceptual sensor via programmable assembly of single-walled carbon nanotubes (SWCNTs) and Ti 3 C 2 T x MXene@MoS 2 nanocomposite in dual-mode triaxial structural aerogel fiber (DM-TSF) for both selective NH 3 and temperature monitoring. The DM-TSF is prepared through triaxial wet spinning, with an alternating p / n -type thermoelectric (TE) core, a signal decoupling aramid nanofibers layer, and an NH 3 sensing outer sheath. The TE core is composed of alternately interconnected p -type/SWCNT and n -type SWCNT/Polyethyleneimine, which exhibits high TE efficiency (8.44 μV K −1 for p -segment, 7.44 μV K −1 for n -segment) and wide-range (10–500 °C) temperature monitoring in DM-TSF. Furthermore, the abundant adsorption sites and high-density Schottky heterojunctions of the Ti 3 C 2 T x MXene@MoS 2 nanocomposite in the outer sheath enabled DM-TSF to exhibit an outstanding sensitivity (3.14% ppm −1 @20 ppm) and high selectivity for NH 3 . A portable wireless system based on DM-TSF was further developed and integrated into firefighting clothing for temperature and NH 3 monitoring, triggering alarms within 2 s and 28 s, respectively. This work sheds new light on the fabrication of intelligent multiplex hazard detection fibers that can respond to multi-hazard elements, thereby enhancing firefighters’ safety in complex fire scenarios. Graphical