Beta vulgaris aided green synthesis of ZnO nanoparticles and their luminescence, photocatalytic and antioxidant properties

Multifunctional zinc oxide nanoparticles (ZnO Nps) were synthesized by solution combustion synthesis using beetroots (Beta vulgaris). The structure and morphology of the product were studied by powder X-ray diffraction, UV-visible spectroscopy and scanning electron microscopy. XRD studies indicate the formation of Nps with hexagonal wurtzite structure having crystallite sizes in the range of similar to 52-76 nm. The UV-visible spectrum of Nps shows maximum absorption at 373 nm. The SEM analysis indicates the formation of porous, sponge-like agglomerated structures. Very interesting room temperature luminescence phenomena were observed with violet, green and red emissions upon exciting the ZnO Nps at 378 nm. This phenomenon could be due to oxygen vacancy and ZnO interstitial defects. ZnO Nps effectively degrade malachite green (MG) and methylene blue (MB) dyes in the presence of UV light. Nps show good antioxidant activity by scavenging 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals. The study successfully demonstrates simple, economical and ecofriendly methods of synthesis of multifunctional ZnO Nps. Nps may be used as good color tunable phosphor materials. The method demonstrated in this study is suggested as an effective replacement for the hazardous chemical methods of production of zinc oxide nanoparticles.