Direct hydrothermal growth of ZnO nanosheets on electrode for ethanol sensing

ZnO nanosheet microstructures have been directly grown on Al2O3 tube electrode by one-step hydrothermal method with different reaction times (3 h, 8 h and 12 h). The crystalline phase, morphology, and structure of the nanosheets are characterized by FESEM, TEM/SAED, and XRD. The results of FESEM reveal that ZnO nanosheets exhibit a sheet networks structure and a lager surface area. TEM/SAED images show a rough surface and a polycrystalline structure of ZnO nanosheets. X-ray diffraction indicated the ZnO architectures are well-crystallized in a hexagonal wurtzite structure. Gas sensing properties of the ZnO nanosheets show high response, fast response-recovery curves and long-term stability to 25-1000 ppm ethanol at appropriate temperature (400 °C), especially for sensor B (8 h). Moreover, the response of sensor B can get up to 38.4 for 100 ppm ethanol, and even 25 ppm ethanol could be well detected with a high response about 15 which is mainly attributed to the high surface area. This demonstrated the great potential application of ZnO nanosheets for developing gas sensors.