Ultrahigh sensitive and selectivity NO2 gas sensors based on Sn-MOF derivates at low temperature

Nitric oxides emission, especially nitrogen dioxide (NO2), has aroused a series of environment and ecological problems and damaged human health, it is of great significance to monitor the NO2 concentration in the atmosphere. However, developing the real-time NO2 sensors remains challenge due to high working temperature, limited sensitivity at the low temperature and poor selectivity. Hence, we designed and synthesized the SnO2-M-OV-T sensors through thermal treating the Sn metal organic frameworks (Sn-MOF), and the prepared SnO2-M-OV-T sensors exhibits the excellent sensing performance under a low operating temperature. The response value of SnO2-M-OV-300 sensor for NO2 could reach 11677 at 120 oC, that is 100 times than pristine SnO2, and the response value of 170 was also achieved even at the low temperature of 50 oC. In addition, the SnO2-M-OV-300 sensor also showed the good cyclicity and stability for NO2 detection. Density functional theory results show that both the oxygen vacancy and Sn atom act as the adsorption and active sites during the process of NO2 gas sensing, yet the role of oxygen vacancy prefers the adsorption and charge transfer for NO2 than of Sn atom. The high-performance SnO2-M-OV-T gas sensors display a broad application prospect in the real-time monitoring NO2 industrial field.