Synthesis and characterization of nickel oxide nanoparticles using Clitoria ternatea flower extract: Photocatalytic dye degradation under sunlight and antibacterial activity applications

The present study is aimed to synthesize nickel oxide nanoparticles (NiO NPs) by using medicinal flower extract of Clitoria ternatea and examine its antibacterial and photocatalytic dye degradation activities. The synthesized NPs were investigated using UV-visible spectroscopy wherein they exhibited a color change pattern and confirmed their maximum absorption peak at 280 nm, which is distinct for NiO NPs. The FTIR analysis showed the presence of various functional groups in the flower extract as well as on the NiO NPs. XRD studies revealed the high crystalline nature of NiO NPs with 9.6 nm average size. The TEM micrograph shows hexagonal shape of the NPs that are non-agglomerated with a particle size of 13 nm. The composition of nickel and oxygen elements was confirmed through EDX studies. Using the well diffusion method, the antibacterial activity of NiO NPs was tested against both gram positive and gram-negative bacterial strains of Staphylococcus aureus and Escherichia coli. Additionally, photocatalytic degradation of Fast Green (FG) and Rose Bengal (RB) dye molecules were performed by using NiO NPs. Based on the obtained results, we confirmed that NiO NPs degrade FG by 89 % and RB by 77 % in the presence of sun light.