Hybridization of nickel oxide nanoparticles with carbon dots and its application for antibacterial activities.

A nickel oxide nanoparticle (NiO NP) composite with carbon dots (C-dots), (NiO NPs@C-dots) was synthesized, characterized, and then its antibacterial activity was evaluated. NiO NPs were prepared using Buddleja polystachya Fresen leaf extract and Ni(NO3 )2 .6H2 O as precursors. The C-dots were synthesized from benzene-1,4-diamine and citric acid. The cubic structure of the NiO NPs and NiO NPs@C-dots was in phase with their average particle size distributions of 21.47 ± 0.56 and 21.61 ± 0.34 nm, respectively. The surface morphology of the NiO NPs@C-dots was characterized using field emission scanning electron microscopy and also revealed a large surface area, which is advantageous for the specified application. The X-ray diffraction result indicated a cubic face wurtzite structure and the crystalline nature of the NiO NPs. Carbon-doped compounds had no influence on the crystal structure of the NiO compound and no new peaks were observed. The antibacterial activity of a composite made up of NiO NPs@C-dots was tested, as well as the antibacterial activities of compounds produced against human photogenic bacterial strains. Both NiO NPs and NiO NPs@C-dots were found to be powerful against all bacterial strains, based on the bioassay results. NiO NPs and NiO@C-dots appeared to display strong to inhibitory effects of 14-20 mm and 17-23 mm, respectively.