Solvothermal Growth of Ultrathin Nonporous Nickel Oxide Nanosheets for Ethanol Sensing

In the present work, nonporous ultrathin nanosheets of nickel oxide (NiO) were successfully fabricated via β-Ni(OH) 2 using solvothermal route. The as-prepared nanosheets of β-Ni(OH) 2 are thermally dehydrated at 573 K for 6 h to produce NiO nanosheets. X-ray diffraction (XRD) investigation confirms the formation of β-form of Ni(OH) 2 and pure crystalline NiO of as-prepared and thermally dehydrated product, respectively. The scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscope (TEM) images of thermally dehydrated powder confirm the formation of ultrathin nonporous hexagonal nanosheets of NiO with thickness of the order of 1–3 nm. UV–Visible studies of NiO nanosheets show the enhanced bandgap (3.8 eV) in comparison to its bulk counterparts (3.54 eV). Current–voltage characteristics were carried out to study the response of NiO nanosheets in the ethanol atmosphere. Decrease in electric current is observed at a given applied potential with respect to time of exposure when the nanosheets of NiO are exposed to ethanol vapors confirming its reducing nature. The sensing studies made are only in qualitative mode.