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 nano sheets 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 degrees 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. (C) 2014 Elsevier B.V. All rights reserved.