Synthesis and characterization of NiO nanostructures: a review

In the last decade, NiO nanostructures (NSs) have gained a growing attention from the scientific community because they are cheap, facile to produce and isolate, and they could be employed in a plethora of application ranging from photoelectrochemical device to smart window, from catalysis to sensor. Throughout this review, the most widely employed and effective synthetic techniques are summarized and their advantages and drawbacks are highlighted and compared. Almost all these synthetic pathways produce amorphous nanostructures that need to be annealed to obtain crystalline products. The quite high temperature required for this procedure is the main issue that prevents the scalability of these procedures. Throughout this review, a brief description of the main experimental techniques employed to characterize the nanostructures is provided as well. The investigated features of these materials deeply depend on the application the latter are produced for.