Facile and eco-friendly combustion synthesis of NiO particles for photodegradation studies

Nickel oxide (NiO) particles were synthesized by varying temperature through solid-state combustion method. The effects of annealing temperatures such as 650, 750, 850, 950, and 1050 degrees C, on the crystallite size, absorption properties, and photodegradation of methylene blue (MB) were studied. Progressive enhancement of crystallinity of the samples was clearly observed in FE-SEM images. The photocatalytic degradation of MB with different crystallite sizes was studied, showing that degradation increases with increasing the sample's crystallinity. The percentage of degradation of MB dye is found to be 96% in three hours. Furthermore, the density functional theory (DFT) studies have been performed for NiO to understand the linear optical and chemical properties. The DFT results are found to have a good correlation with the experimental findings.