Porous ZnO microflowers with ultrahigh sensitive and selective properties to ethanol

The porous ZnO microflowers, which looks like a flower, has been successfully prepared by a simple hydrothermal method. The structure and morphology of the samples were characterized by X-ray diffraction and Scanning electron microscopy. Meanwhile, the as-prepared samples were applied to fabricate gas sensor device, the gas sensing properties of the sensors based on porous ZnO microflowers were studied. The results indicate the ultrahigh sensitivity and excellent selectivity of Porous ZnO microflowers sensors to ethanol. The response of Porous ZnO microflowers sensor to 100 ppm ethanol is about 123 at 260 °C, which is 4.1 times larger than that of acetone (the response value is 30). The ZnO sensors can successfully distinguish acetone and ethanol which possess similar properties. The results demonstrate that the ZnO sensors have an excellent selectivity to ethanol. The response and recovery time are 4 and 12 s to 50 ppm ethanol, respectively. Moreover, the concentration of ethanol that we can detect is 0.2 ppm, and the response value is 1.65. Thus this work is confirmed that the porous ZnO microflowers sensors have a fantastic gas sensitive property for ethanol.