The synthesis of flower-like layered double hydroxides nanocrystals and their calcined products

This paper describes a facile solvothermal method to synthesize self-assembled three-dimensional (3D) Ni²⁺-Fe³⁺ layered double hydroxides (LDHs) nanocrystals. Flower-like Ni²⁺-Fe³⁺ LDHs constructed of thin nanopetals were obtained using ethylene glycol (EG) as a chelating reagent and urea as a hydrolysis agent. The reaction mechanism and self-assembly process are discussed. After calcinating the as-prepared LDHs at 450 °C in nitrogen gas, porous NiO/NiFe₂O₄ nanosheets were obtained. This work resulted in the development of a simple, cheap, and effective route for the fabrication of large area Ni²⁺-Fe³⁺ LDHs as well as porous NiO/NiFe₂O₄ nanosheets.