Synthesis and gas sensing properties to NO2 of ZnO nanoparticles

In this work, we prepared ZnO nanoparticles with sizes ranging from 5 to 270 nm by annealing the precursor of zinc carbonate hydroxide at four different temperatures (200, 400, 600 and 800 degrees C) and investigated their morphology, structure and optical properties as well as sensing performances to NO2. The precursor with small particle size and narrow size distribution was synthesized by a simple method involving separate nucleation and aging steps (SNAS). Among four obtained ZnO samples, the ZnO-400 (annealed at 400 degrees C) exhibits the best optical properties and the highest sensing response to NO2. The ZnO-400 shows fast response (<= 30 s) and recovery (<= 120 s) to NO2 and high selectivity to NO2. Besides, we further discussed a correlation between the gas sensing response and the defects of ZnO nanoparticles. (c) 2013 Elsevier B.V. All rights reserved.