Controlled Synthesis of Hierarchically Assembled Porous ZnO Microspheres with Enhanced Gas-Sensing Properties

Shengsheng You,Jing Qian,Ya-Li Sun,Haojie Song,Xiao-Hua Jia

doi:10.1155/2015/680306

Abstract

The ZnO microspheres constructed by porous nanosheets were successfully synthesized by calcinating zinc hydroxide carbonate (ZHC) microspheres obtained by a sample hydrothermal method. The samples were characterized in detail with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric and differential scanning calorimetry (TG-DSC). The results indicated that the prepared ZnO microspheres were well crystalline with wurtzite hexagonal phase. The effects of reaction time, temperature, the amount of trisodium citrate, and urea on the morphology of ZnO microspheres were studied. The formation mechanism of porous ZnO microspheres was discussed. Furthermore, the gas-sensing properties for detection of organic gas of the prepared porous ZnO microspheres were investigated. The results indicated that the prepared porous ZnO microspheres exhibited high gas-sensing properties for detection of ethanol gas.

Highlights

Zinc oxide (ZnO) is one of the most important n-type semiconductor materials with a direct wide band gap (3.37 eV) and large excitation binding energy (60 meV) [1]
No characteristic peaks of other impurities were detected in the X-ray diffraction (XRD) patterns, indicating that the porous ZnO microspheres had high purity and good crystallinity
The morphology and microstructure of the zinc hydroxide carbonate (ZHC) precursors and the ZnO microspheres were examined by scanning electron microscopy (SEM) (Figure 2)

Summary

Introduction

Zinc oxide (ZnO) is one of the most important n-type semiconductor materials with a direct wide band gap (3.37 eV) and large excitation binding energy (60 meV) [1]. Cai et al [29] reported that awl-like ZnO nanostructures have been fabricated by sublimation process employing chemical vapor deposition (CVD) method. These synthesis methods typically involve complex controlling process and too much energy, which possibly result in the increased cost and limitation of the potential applications. The prepared samples exhibited excellent sensing performance to ethanol gas, and the porous ZnO microspheres were promising candidates for the applications of ethanol sensitive material

Experimental Section

Results and Discussion

12 Ethanol

Conclusions