A new route for synthesis of spherical NiO nanoparticles via emulsion nano-reactors with enhanced photocatalytic activity

•Types of nickel oxide nanostructures were synthesized by four different chemical methods.•Effects of different morphologies of the nickel oxide nanostructures were examined for MeO degradation.•Uniform morphology & non-agglomerated NiO NPs made via ENRs route at ambient condition.•Spherical NPs of nickel oxide exhibited higher photocatalytic activity.

This study has sought to draw a comparison among the nickel oxide nanostructures (NSs) with multiple shapes in terms of their photocatalytic properties. These NSs have been synthesized using a set of wet chemical methods (thermal-decomposition, sol–gel, hydrothermal, and emulsion nano-reactors), for which a similar precursor has been considered. For evaluation of the photocatalytic properties of the suggested NSs, methyl orange (MeO) solution photocatalytic degradation has been estimated based on UV–Vis spectroscopy. As shown by our results, the photocatalytic efficiency of the prepared NSs is highly dependent upon the shape of the corresponding structures. In this context, the emulsion nano-reactors (ENRs) method has been developed for the synthesis of pure nickel oxide nanoparticles (NPs) with unaggregated, quite spherical, and homogeneous NPs at environmental conditions. Compared with the other methods in this work, ENRs method shows high photocatalytic efficiency in the MeO dye decomposition.

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