The ammonia modified ZIF-8@SnO2 core-shell nanosheets for improved the sensitivity and selectivity of NO2

For NO 2 , a gas that is widely used and harmful, domestic and foreign researchers have done a lot of work to develop a sensor with low detection limit and low humidity sensitivity to achieve efficient detection of NO 2 . In this work, first of all, dense and uniform SnO 2 nanosheets were grown in situ on the surface of Al 2 O 3 ceramic tube by hydrothermal method. Then, the ZIF-8@SnO 2 porous composite gas-sensitive material was constructed by solvent thermal method. With the advantages of the ZIF-8 porous screening framework, the permeation of different gases can be selectively controlled, and the adsorption efficiency of NO 2 gas can be enhanced through the modification of ammonia to improve the selectivity of NO 2 . The results show that the response of the Modified-ZIF-8@SnO 2 sensor is significantly enhanced, and the selectivity is greatly improved at low operating temperature. At 140 °C, the response of Modified-ZIF-8@SnO 2 to 50 ppm NO 2 gas is as high as 61, which is about 18.4 times higher than that of SnO 2 nanosheets and about 16.3 times higher than that of ZIF-8@SnO 2 . Meanwhile, the anti-interference ability of the Modified-ZIF-8@SnO 2 sensor to humidity has been improved. This work provides a new idea for improving the selectivity and humidity insensitivity of gas sensors.