Synthesis of wide band gap nanocrystalline NiO powder via a sonochemical method

A sonochemistry-based synthesis method was used to produce nanocrystalline nickel oxide powder with ∼20 nm average crystallite diameter from Ni(OH)2 precursor. Ultrasound waves were applied to the primary solution to intensify the Ni(OH)2 precipitation. Dried precipitates were calcined at 320 °C to form nanocrystalline NiO particles. The morphology of the produced powder was characterized by transmission electron microscopy. Using sonochemical waves resulted in lowering of the size of the nickel oxide crystallites. FT-IR spectroscopy and X-ray diffraction revealed high purity well-crystallized structure of the synthesized powder. Photoluminescence spectroscopy confirmed production of a wide band-gap structure.

► A sonochemistry-based synthesis method was used to produce nanocrystalline nickel oxide powder.
► The produced nanocrystalline NiO powder has ∼20 nm average crystallite diameter.
► The synthesized powder show a wide band gap in comparison with the values of coarse grained powder reported in literature.
► Wide band gap can be related to the defective nanostructure of them caused by cavitation phenomenon.