ZIF-8 derived hierarchical hollow ZnO nanocages with quantum dots for sensitive ethanol gas detection

As an important semiconductor metal oxide, zinc oxide has been intensely investigated for the application of gas-sensing. Herein, we developed a metal-organic framework (MOF)-based strategy to synthesize novel hierarchical hollow ZnO nanocages with quantum dots (denoted as HHQD-ZnO nanocages). For comparison, solid ZnO and hollow ZnO nanocages derived from the rhombic dodecahedral (RD) ZIF-8 and 470-ZIF-8, respectively have also been synthesized. Gas sensing measurement indicated that the sensor based on the HHQD-ZnO nanocages exhibits super high response of 139.41 upon 100 ppm ethanol at 325 degrees C. In addition, the HHQD-ZnO nanocages-based sensor can detect ethanol gas at a detection limit of well below 25 ppb with the response of 5.1. Such excellent performance, especially the ultrahigh response to ethanol is explained with respect to particle-inter-penetrating framework with good connectivity, hierarchical porous hollow nanostructure and quantum dots.