Selective quantification of nitrogen dioxide in the presence of interfering gases via electronic modulation of MoS ₂ by Ru doping

Abstract Nitrogen dioxide (NO 2 ) is a significant air pollutant with harmful effects on human health and the environment. Timely and accurate monitoring of NO 2 concentrations is crucial for improving air quality and protecting public health. However, quantifying NO 2 in the presence of other gases remains challenging. Herein, we integrate Ru onto the MoS 2 surface to form Ru–S–Mo active sites, thereby tuning the electronic structure of MoS 2 for enhanced NO 2 detection. This sensor shows excellent sensitivity (29.7% at 100 × 10 −6 NO 2 and 25 °C), with a linear response to NO 2 ranging from 0.5 to 200 × 10 −6 , and a significantly reduced response/recovery time from 160/3636 s for pure MoS 2 to 58/427 s for Ru@MoS 2 at 100 × 10 −6 NO 2 . Additionally, the sensor is highly selective for NO 2 , exhibiting a response 14 times higher than for other gases, and possesses strong anti‐interference capabilities, accurately quantifying NO 2 in the presence of varying H 2 concentrations (10 × 10 −6 –200 × 10 −6 ) with a low RSD of 5.34%. A portable wireless NO 2 monitoring system was successfully constructed using Ru@MoS 2 , enabling real‐time gas leak detection (10 × 10 −6 –50 × 10 −6 ) with hazard warnings and maintaining a stable response to NO 2 over a 4‐week period. This work extends the gas sensing applications of MoS 2 and provides a portable, wireless, and high‐selectivity NO 2 sensing method for environmental monitoring and safety assurance.