SO <sub/>2</sub> -sensing properties of NiO nanowalls synthesized by the reaction of Ni foil in NH <sub/>4</sub> OH solution

摘要： Nickel oxide (NiO) is a p-type metal-oxide semiconductor with wide-ranging applications. Recent studies have focused on the gas-sensing properties of this semiconductor. This study introduces an easy process for growing NiO nanowalls on a glass substrate using Ni foil and aqueous NH4OH. The morphology and structure of the NiO nanowalls are investigated and confirmed by field-emission scanning electron microscopy and x-ray diffraction (XRD) analyses. The gas-sensing properties of the prepared nanowalls are tested using a dynamic gas-testing system wherein the target gases are H2S, NO2, NH3 and SO2. Gas-sensing data show that the synthesized NiO nanowalls are highly responsive toward SO2. Additionally, a sensing device prepared based on the NiO nanowalls is found to be stable during measurements, exhibiting a linear variation with changes in SO2 concentration.