Time‐Frequency Domain NO ₂ ‐Humidity Sensor with Full‐Range Tolerance Based on Pt Single‐Atom Sensitized Nb ₂ CT <i> _x </i> Nanosheets

Abstract

Abstract Real‐time in situ detection of NO 2 is crucial for ensuring industrial safety and healthcare. However, conventional gas sensors face challenges from environmental humidity interference, limiting their reliability in practical applications. This study presents a dual‐mode, full‐range NO 2 ‐humidity sensing platform based on Pt single‐atom‐sensitized Nb 2 CT x nanosheets (Pt SA‐Nb 2 CT x ) integrated with TPU fiber mats (Pt SA‐Nb 2 CT x @TPU). Combining resistive gas sensing and capacitive humidity sensing within a single device, this platform enables simultaneous NO 2 and humidity detection with full‐range humidity tolerance. The uniformly dispersed Pt single‐atoms on the Nb 2 CT x nanosheets catalyze oxygen molecule dissociation and provide additional surface‐active adsorption sites, achieving a 9.1‐fold improvement in resistance response to 5 ppm NO 2 and a 25.7‐fold increase in capacitance response at 95% relative humidity. Importantly, the unaffected capacitive response allows precise calibration of NO 2 concentration using resistance and capacitance, ensuring accurate NO 2 detection across diverse and fluctuating humidity. Leveraging time‐ and frequency‐domain NO 2 ‐humidity sensing capability, the Pt SA‐Nb 2 CT x @TPU sensor is successfully integrated into self‐designed functional modules to realize humidity tracking, industrial NO 2 concentration alarming in full‐humidity range as well as asthma prevention and alarm applications. This study offers a novel solution for humidity‐compensated NO 2 detection, advancing the applicability of gas sensors in complex and dynamic environments.