Biogenic synthesis and characterization of zinc oxide nanoparticles for effective and rapid catalytic reduction of 4-nitrophenol

This paper discusses the biogenic synthesis of zinc oxide (ZnO) nanoparticles by using aqueous solutions of zinc acetate dihydrate and Ocimum tenuiflorum leaf extract. Field emission scanning electron microscopy (FE-SEM) confirms the formation of fine ZnO aggregates. Crystallographic structure and functional group of the nanoparticles are determined by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) techniques. UV-visible and fluorescence spectroscopies are employed to assess optical behaviour of ZnO nanoparticles.The ZnO nanoparticles show nearly 100 % catalytic efficiency in the sodium borohydride (NaBH4)-mediated reduction of 4-nitrophenol within 60 s. Also, the catalyst can be reused for five cycles without losing 100 % regeneration efficiency. This study demonstrates that the prepared ZnO nanoparticles can effectively detoxify 4-nitrophenol from an aqueous solution.