Porous nanoplate-assembled CdO/ZnO composite microstructures: A highly sensitive material for ethanol detection

Hierarchical CdO/ZnO composite materials composed of porous nanoplates are prepared by simple thermal treatment of a pre-synthesized cadmium-zinc bimetallic carbonate precursor. The gas-sensing properties of the as-synthesized nanocomposites are evaluated by a range of gases and organic vapors, and the results show that the gas sensors based CdO/ZnO nanocomposites exhibit the highest sensing response towards ethanol relative to other testing gases. The optimal ratio of CdO to ZnO in CdO/ZnO nanocomposites is 7.5: 100 for ethanol detection. The highest response of CdO/ZnO is similar to 7 and 59 times as high as those of the pure ZnO and the pure CdO, respectively. The significantly enhanced sensing performance of the CdO/ZnO nanocomposite is attributed to its novel hierarchical structure and synergetic effect between CdO and ZnO. In addition, the CdO/ZnO sensor short response and recovery times (<10 s) and a wide response range from 0.5 to 500 ppm for ethanol detection. In the testing range from 0.5 to 500 ppm, the logarithm of sensitivity shows a good linear dependency on the logarithm of ethanol concentration, indicating that the CdO/ZnO sensor may be used for quantitative detection of ethanol vapor. (C) 2014 Elsevier B.V. All rights reserved.