Wearable and Highly Sensitive Sensing Fiber Enabled by Mesoporous MXene and MXene/SnSe for Ammonia Gas and Temperature Monitoring of Firefighting Clothing

Traditional firefighting clothing plays a crucial role in protecting firefighters from burn injuries through its passive heat insulation performance. However, current firefighting garments still face a challenge in dealing with complex and changeable rescue scenarios due to their insufficient risk warning capability for firefighter safety. Herein, we propose a wearable bimodal fiber sensor with a core-sheath structure, which incorporates an engineered mesoporous Ti 3 C 2 T x and a Ti 3 C 2 T x /SnSe heterojunction integrated into an aramid nanofiber substrate for monitoring exposed ammonia gas and temperature in firefighting clothing. The outer shell of sensing fiber is composed of mesoporous Ti 3 C 2 T x, featuring active edge-Ti-O sites, while the MXene and SnSe in the core layer of the sensing fiber create nanoscale Schottky junctions that facilitate an energy filtering effect. The resulting chemical resistance-type gas sensing fiber sheath provides an ultrafast response time (9 s) and high sensitivity (41.76% @ 8 ppm) in detecting NH 3 . Additionally, due to the energy filtering effect of the nanoscale Schottky junction between Ti 3 C 2 T x and SnSe, the sensing fiber core exhibits high thermoelectric sensitivity ( S = 560 μV K −1 from 130 to 320 °C), super-resolution (1 °C), and a wide temperature monitoring range (−20 to 320 °C). To facilitate wearable applications, the sensing signals from the monitoring system are transmitted wirelessly via Bluetooth and displayed on a smartphone, enabling multidirectional dynamic warnings for NH 3 and overheating alerts in firefighting clothing. This work significantly advances the implementation of wearable gas and temperature warning sensors in firefighting clothing for enhancing firefighter safety.