The green approach of ZnO NPs and its Antioxidant, hemolytic, and photocatalytic activity and functionalized r-GO-ZnO for energy storage application

The present paper describes the green synthesis of Zinc oxide nanoparticles (ZnO NPs) from the flowers of L. nepetifolia . Zinc oxide nanoparticles have gained more interest from researchers due to their wide applications from biological activity to energy storage system. The synthesis of ZnO nanoparticles and examined by using Ultraviolet–visible spectroscopy, Fourier Transform-Infrared spectroscopy, X-ray Diffraction analysis, Dynamic Light Scattering analysis, Raman spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-ray spectroscopy, BET, XPS, Transmission Electron Microscopy, and Thermogravimetric Analysis. The photocatalytic studies were followed using methylene blue (MB) dye by ZnO nanoparticles by using sunlight as a source. The degradation of MB dye is found to be 90% within 70 min. Then the synthesized ZnO nanoparticles help to evaluate the antioxidant activities against Nitric oxide, Hydrogen peroxide, and DPPH free radicals. Moreover, the synthesized ZnO NPs show good biocompatibility nature, and the electrochemical analysis of reduced Graphene Oxide with Zinc oxide (rGO-ZnO) nanocomposite shows that the prepared rGO-ZnO nanocomposite has a high specific capacitance of about 667 F g −1 in comparison with the pure Zinc oxide nanoparticles (200 F g −1 ) and has good cycling stability over 1000 cycles.