Morphological evolution of self-supporting nickel hydroxide nanostructures prepared by a facile wet-chemical method

Curved and nanolayered structures of nickel hydroxide (Ni(OH)2) were synthesized via a facile wet-chemical process. After nanoparticles of less than 100 nm formed during the initial reaction stage, two-dimensional (2D) nanosheets were obtained. With increasing reaction times, the nanosheets became interconnected with each other, resulting in the formation of nanolayered structures. Moreover, semi-transparent self-supporting Ni(OH)2 films with areas on the order of square centimeters were obtained after drying at 90 °C. Annealing at 500 °C caused the dehydration of hydroxide phase (Ni(OH)2), leading to the formation of oxide phase (NiO). During this phase transition, the curved and nanolayered structures maintained their shape, while each individual nanosheet was embedded with sub-level nanoparticles.