Effect of Fe doping on the structural and gas sensing properties of ZnO porous microspheres

Fe-doped ZnO porous microspheres composed of nanosheets were prepared by a simple hydrothermal method combined with post-annealing, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller N-2 adsorption-desorption measurements and photoluminescence (PL) spectra. In this paper we report Fe doping induced modifications in the structural, photoluminescence and gas sensing behavior of ZnO porous microspheres. Our results show that the crystallite size decreases and specific surface area increases with the increase of Fe doping concentration. The PL spectra indicate that the 4 mol% Fe-doped ZnO has higher ratio of donor (V-O and Zn-i) to acceptor (V-Zn) than undoped ZnO. The 4 mol% Fe-doped ZnO sample shows the highest response value to ppb-level n-butanol at 300 degrees C, and the detected limit of n-butanol is below 10 ppb. In addition, the 4 mol% Fe -doped ZnO sample exhibits good selectivity to n-butanol. The superior sensing properties of the Fe-doped porous ZnO microspheres are contributed to higher donor defects contents combined with larger specific surface area. (C) 2014 Elsevier Ltd. All rights reserved.