Synthesis of monodisperse ZnO hollow six-sided pyramids and their high gas-sensing properties

Monodisperse ZnO hollow six-sided pyramids were successfully synthesized by a low-cost and simple hydrothermal method at 160 degrees C for 20 h without the use of any surfactant or template. The sodium citrate (Na3C6H5O7 center dot 2H(2)O) and glycerol (C3H8O3) played a pivotal role in the growth of hollow six-sided pyramid, and the possible growth mechanism was also proposed based on the experimental facts. Moreover, the gas sensor based on this structure displayed excellent gas sensing properties to ethanol at the optimum operating temperature of 240 degrees C. The response was about 187 and the response-recovery time was around 11 and 9 s for 200 ppm ethanol, respectively, which indicated that this structure had high sensitivity, fast response-recovery time and good selectivity to ethanol. (C) 2015 Elsevier B.V. All rights reserved.