Selective detection of ethanol at low concentration by ZnO@ZIF-8 porous nanosheets

Abstract

Effectively improve the sensitivity of semiconductor gas sensors, reduce the working temperature and improve its detection ability at low concentrations are priority for practical applications. However, the design of appropriate sensing materials has become a great challenge. Herein, two-dimensional (2D) ZnO@ZIF-8 porous nanosheets (PNSs) heterostructures are prepared via a facile solvothermal method for ethanol detection. ZIF-8 can be used as a “breathable” support/filter layer to reduce self-accumulation of ZnO PNSs. ZnO@ZIF-8–24 exhibits an enhanced response (Ra/Rg=58) with high selectivity (SEthanol/SInterfering values ranged from 2.1 to 25.2) toward 50 ppm ethanol at 240 °C compared to ZnO. Meanwhile, ZnO@ZIF-8 (Ra/Rg=7.2) has better response than ZnO (Ra/Rg=2.8) at low concentration (5 ppm).The enhancement is ascribed to the increased exposure of active sites due to the inhibition of self-stacking of two-dimensional porous nanosheets by ZIF-8 nanoparticles. Furthermore, the heterostructures can strengthen the electron transfer and adsorption of ethanol molecules on ZIF-8. Thus, our research provides a new approach for the application of 2D heterostructures in gas sensing.