Room-Temperature-Operable and Cost-Effective CO₂ Sensor for Monitoring Respiratory Health

Driven by the rising prevalence of respiratory diseases and the increasing demand for portable medical devices, the development of innovative CO₂ sensing materials that operate at room temperature - while ensuring cost-effectiveness and biosafety - is crucial for the widespread adoption of early screening for respiratory disorders and daily health monitoring. Herein, Cu-Al dual-atom anchored on nitrogen-doped carbon nanofibers (CuAl-NCFs) were fabricated via electrospinning and employed to construct a chemiresistive CO₂ gas sensor operable at room-temperature. Among all samples, the 8.3 wt.% CuAl-NCFs-based sensor shows the best overall CO₂ sensing performance, with a relative response value of -4.04% (ΔR/R₀) at 4% CO₂ and a recovery time of 63 s, together with good reversibility and repeatability. Moreover, this sensor enables real-time monitoring of exhaled CO₂ at different sensor-to-nose distances, demonstrating its potential for non-contact breath monitoring. The enhanced sensing performance is primarily attributed to the synergistic interaction between atomically dispersed Cu and Al sites, which improves the adsorption capacity for CO₂ molecules. This work offers a novel strategy for designing dual-atom gas-sensing materials suitable for wearable medical monitoring systems.