Supersensitive and superselective formaldehyde gas sensor based on NiO nanowires

In this work, nickel oxide (NiO) nanowires were synthesized by a simple hydrothermal route using NiCl2·6H2O, Na2C2O4 and ethylene glycol (EG) as precursors at 220 °C for 12 h. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmittance electron microscopy (TEM), scanning electron microscopy (SEM). The crystal structure of prepared NiO nanowires is cubic phase polycrystalline. The average nanowires diameter is ∼120 nm. The gas sensing properties of the as-prepared NiO nanowires toward formaldehyde were investigated.