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

Nitric oxides emission, especially nitrogen dioxide (NO 2 ), has aroused a series of environment and ecological problems and damaged human health, it is of great significance to monitor the NO 2 concentration in the atmosphere. However, developing the real-time NO 2 sensors remains challenge due to high working temperature, limited sensitivity at the low temperature and poor selectivity. Hence, we designed and synthesized the SnO 2 -M-O V - T sensors through thermal treating the Sn metal organic frameworks (Sn-MOF), and the prepared SnO 2 -M-O V - T sensors exhibits the excellent sensing performance under a low operating temperature. The response value of SnO 2 -M-O V -300 sensor for NO 2 could reach 11677 at 120 °C, that is 100 times than pristine SnO 2 , and the response value of 170 was also achieved even at the low temperature of 50 °C. In addition, the SnO 2 -M-O V -300 sensor also showed the good cyclicity and stability for NO 2 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 NO 2 gas sensing, yet the role of oxygen vacancy prefers the adsorption and charge transfer for NO 2 than of Sn atom. The high-performance SnO 2 -M-O V - T gas sensors display a broad application prospect in the real-time monitoring NO 2 industrial field.