Assembly of 2D nanosheets into 3D flower-like NiO: Synthesis and the influence of petal thickness on gas-sensing properties

We report a successful synthesis of three hierarchical NiO nanoflowers via a surfactant-assisted hydrothermal method. We find that the NiO hierarchical architectures are self-assembled by uniform nanosheets with different petal thicknesses. Moreover, we develop gas sensors based upon the nanomaterials and demonstrate that the nanoflower with the thinnest petal exhibits the best gas-sensing functionalities. By conducting a comprehensive characterization of microstructures and morphologies of the nanomaterials, we propose a possible nucleation-growth mechanism and explain how the petal thickness affects the gas-sensing properties of the nanoflowers.