Solution plasma synthesized nickel oxide nanoflowers: An effective NO2 sensor

Nickel oxide (NiO) nanoflowers were successfully prepared, for the first time, from a mixture of Ni(NH3)62+ and triethanolamine via a solution plasma process. The as-synthesized samples were characterized by X-ray powder diffraction, scanning electron microscopy, nitrogen adsorption–desorption isotherms and transmission electron microscopy. Based on the experimental results, a possible formation mechanism for the NiO nanoflowers was proposed. In addition, the gas responses of NiO nanoflowers were investigated towards 100 ppm of a variety of gases including H2, NO2, CO, toluene, NH3, and H2S at 150 °C. It was found that NiO nanoflowers are promising NO2 sensing materials owing to their excellent response and selectivity.

► NiO nanoflowers were prepared via a solution plasma process.
► A possible formation mechanism of NiO nanoflowers was proposed.
► NiO nanoflowers are promising as an NO2 gas sensor.