A comparative study of porous ZnO nanostructures synthesized from different zinc salts as gas sensor materials

Abstract

Abstract Three porous ZnO nanostructures were synthesized by annealing their basic zinc carbonate (BZC) precursors, which were prepared via a simple hydrothermal process using urea solution with different zinc salts (zinc acetate, zinc chloride or zinc sulfate) under the same conditions. The influences of different anonic species (CH 3 COO − , Cl − and SO 4 2 - ) on the morphologies, structures and gas sensing performances of the obtained porous ZnO nanostructures have been reported. The products were characterized by XRD, TG-DSC, FTIR, SEM, TEM and BET. All the BZC precursors are the mixture of Zn 5 (CO 3 ) 2 (OH) 6 and Zn 4 CO 3 (OH) 6 ·H 2 O. After annealing, porous ZnO nanostructures obtained from zinc sulfate show the largest specific surface areas. SAED patterns of the same size selected area (500 nm in diameter) show that the porous ZnO nanostructures obtained from zinc sulfate and zinc chloride often display polycrystalline nature, while those obtained from zinc acetate often display single or quasi-single crystalline nature. The gas sensing performances of these three porous ZnO nanostructure samples toward some typical volatile organic compounds (including acetone, 2-chlorophenol and formaldehyde, etc.) were investigated comprehensively. The porous ZnO nanostructure obtained from zinc sulfate shows the most superior gas-sensing properties, followed in turn by the ZnO samples obtained from zinc chloride and zinc acetate. The results are tentatively attributed to the different total specific surface area, crystalline nature and accumulated morphologies of the porous ZnO samples.