Facile Non-Template Synthesis Mesoporous Hollow Sphere Zinc Oxide for High Gas Sensitive Ethanol Detection

Abstract

Porous microstructures are playing more and more important role in developing new gas sensor with high gas-sensing performance due to their large specific surface area, high void fraction and many active sites. Therefore, a stable and facile synthesis method to synthesize porous microstructures is beneficial for a wide range of applications. Herein, we have used a facile hydrothermal method to achieve the controlled synthesis of various morphologies of ZnO such as solid sphere; mesoporous sphere; flocculent sphere and snow flower-like by simply regulating the temperature and time of the reaction, and apply these materials to gas sensors. As a result, gas sensing investigation demonstrates that the gas sensor based on the mesoporous sphere, flocculent sphere and snow flower zinc oxide microstructures can detect as low as 500 ppb ethanol at 250 o C with the response value of ~1.3. Especially, the gas sensor based on the mesoporous sphere zinc oxide has the highest gas response of ~51.7 to 100 ppm ethanol at 250 o C, which is about 7 times higher than that of solid sphere zinc oxide (~7.3) under the same condition. We believe that this work is meaningful for the synthesis of metal oxides with peculiar morphologies and provide a new strategy for the enhancement of gas sensing properties. The mechanisms of the structure formation and the enhanced gas-sensing properties are also discussed systematically.

Keywords: mesoporous hollow sphere, pure zinc oxide, ethanol gas sensor, high gas response, low detection limit