N-/S- dual doped C@ZnO: An excellent material for highly selective and responsive NO2 sensing at ambient temperatures

Nitrogen dioxide (NO2) is an extremely toxic gas and harmful to human health and the environment. Inhalation of NO2 reduces immunity to lung infections and causes respiratory problems such as wheezing, coughing, colds, flu, and bronchitis. To date, several sensors have been developed for the detection of NO2. Indeed, the development of highly sensitive and selective room temperature sensor with rapid response and recovery time could be called an innovation for metal oxide-based gas sensors for environmental remedy applications. Herein, we prepared ZnO nanospheres (ZNS), nitrogen-doped carbon-coated ZnO spheres (NC@ZNS), sulfur-doped carbon-coated ZnO spheres (SC@ZNS), and nitrogen-sulfur dual doped carbon-coated ZnO spheres (NSC@ZNS) for NO2 sensing. Among them, the NSC@ZNS exhibits excellent NO2 sensing characteristics with the sensor response (S-R = R-g/R-a) of 730.4 and 31.2 at 100 and 25 degrees C, respectively. The limit of detection (LOD) of the NSC@ZNS sensor is similar to 21 ppb at ambient temperature. The NSC@ZNS hybrid nanocomposite sensor exhibits ultrafast response and recovery times of similar to 88 s and 305 s to 500 ppb of NO2 at 25 degrees C. Besides, the NSC@ZNS sensor shows excellent selectivity to NO2, which is similar to 31 times higher than other interfering gases. The enhanced sensing characteristics of the NSC@ZNS sensor is attributed to the synergy between the nitrogen-sulfur dual doped carbon and hierarchical mesoporous ZnO. The selective detection of NO2 with significantly rapid response and recovery time at 25 degrees C makes for intriguing the promising practical applications of our proposed NSC@ZNS sensor.

Automated summary

Researchers have developed a new sensor NSC@ZNS with excellent sensing characteristics for NO2, with high sensitivity and rapid response. The sensor has a detection limit of 21 ppb at ambient temperature, and demonstrates superior selectivity to NO2.