Template-free hydrothermal synthesis of ZnO micro/nano-materials and their application in acetone sensing properties

ZnO micro/nano-materials with sheet and rod morphologies were hydrothermally synthesized with template-free. In synthesis, NaOH was used as the precipitant. The mass ratio of NaOH to zinc salt was the key factor in control the morphology of ZnO product, and synthesized ZnO exhibited a hexagonal wurtzite structure. The gas-sensing properties of the sensors based on the ZnO nanosheets and rods were systematically investigated. At 220 degrees C, the sensitivity of ZnO nanosheet to 100 ppm acetone was up to 24.9, and the response and recovery times were about 4.9 and 3.1 s, respectively, which was superior to the ZnO rods. The results indicated that ZnO products were potential candidates for acetone sensors, and ZnO nanosheets had a more excellent gas performance than ZnO rods (21.21, 6.0 and 3.2 s). Moreover, the formation and gas-sensing mechanisms of different morphologies of ZnO products were discussed. (C) 2014 Elsevier Ltd. All rights reserved.