Enhanced selectivity and response performance of the NO2 sensor composed of ZIF-71-coated In2O3 nanorods grown vertically on ceramic tubes

In 2 O 3 , as a traditional metal oxide semiconductor substrate material, responds to various toxic and harmful gases but with poor selectivity. This paper uses the hydrothermal method to grow dense and uniform In 2 O 3 nanorods vertically on a ceramic tube, and then covers them with ZIF-71. By adjusting the type of solvent used to synthesize ZIF-71, the morphology and properties of the material can be changed. The pores and large specific surface area of ZIF-71 are utilized to sieve large molecular gases, providing more adsorption sites for NO 2 gas. And it forms heterostructure with In 2 O 3 to enhance the response to NO 2 . The optimized gas sensor In 2 O 3 @ZIF-71(CH 3 OH) shows superior response (185, S=R g / R a ) and selectivity of 50 ppm triethylamine as an interfering gas (7.23, S=R a / R g ) to 50 ppm NO 2 compared to pure In 2 O 3 nanorods. Molecular dynamics simulation is used to study the gas adsorption performance of ZIF-71 and theoretical simulation of the adsorption behavior of NO 2 on the In 2 O 3 substrate is conducted through density functional theory. The simulation results show that the ZIF-71 molecular sieve can reduce the response to large molecule TEA gas through the dual effects of pore size adsorption and blocking, thereby improving the selectivity of the material. Indium oxide (In 2 O 3 ) has an adsorption effect on nitrogen dioxide (NO 2 ), with an adsorption heat of 0.499 electron volts, and its adsorption effect is relatively stable.