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

For NO2, 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 NO2. In this work, first of all, dense and uniform SnO2 nanosheets were grown in situ on the surface of Al2O3 ceramic tube by hydrothermal method. Then, the ZIF-8@SnO2 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 NO2 gas can be enhanced through the modification of ammonia to improve the selectivity of NO2. The results show that the response of the Modified-ZIF-8@SnO2 sensor is significantly enhanced, and the selectivity is greatly improved at low operating temperature. At 140 oC, the response of Modified-ZIF-8@SnO2 to 50 ppm NO2 gas is as high as 61, which is about 18.4 times higher than that of SnO2 nanosheets and about 16.3 times higher than that of ZIF-8@SnO2. Meanwhile, the anti-interference ability of the Modified-ZIF-8@SnO2 sensor to humidity has been improved. This work provides a new idea for improving the selectivity and humidity insensitivity of gas sensors.