Temperature dependent dual functional SnO₂ sensor for Cl₂ and NO₂

Gas sensors play a crucial role in monitoring toxic and harmful gases. A large number of sensors or frequent replacement of different sensors is used to meet the purpose of testing different target gases, in order to meet multiple gas monitoring requirements of complex industrial and living environments. The increase in energy consumption and costs has forced the development of sensors capable of monitoring two or more gases. Herein, the SnO₂ thin film assembled from nanoparticles (4-6 nm) was prepared in situ using hydrothermal method. The sensor prepared by the SnO₂ thin film can achieve dual functional sensing of Cl₂ and NO₂ by adjusting the working temperature. At 50 °C, the response of the SnO₂-10 thin film sensor to 5 ppm Cl₂ was as high as 1386. When the working temperature was adjusted to 90 °C, the SnO₂-10 thin film sensor had excellent sensing performance toward NO₂, achieving the high response of 417 and the short recovery time of 15 s for 5 ppm NO₂. Moreover, the SnO₂-10 thin film sensor also demonstrated good reproducibility, reliable long-term stability, and excellent moisture resistance. This work will inspire the synthesis of multifunctional sensing materials and boost their sensing performance and sensing mechanism exploration.