Single step green synthesis of stable nickel and nickel oxide nanoparticles from Calotropis gigantea: Catalytic and antimicrobial potentials

Abstract

Nickel (Ni) and nickel oxide (NiO) nanoparticles (NPs) were successfully synthesized by using a simple, novel and green synthetic route using metal salt and leaves extract of a wild plant “Calotropis gigantea” which act as reducing as well as stabilizing agent due to extra availability of phenolic contents and antioxidants in it. Optimization was carried out by varying different parameters controlling the reaction and the best yield was obtained at 80°C temperature, 90 min incubation time, pH 12, 1 mM precursor concentration and 20% extract concentration. Characterization was made by using various characterizing techniques. UV/VIS absorption peak was at 400 nm for synthesized Ni NPs and at 415 for NiO NPs. The average size of the particles was 20–40 nm, in the case of NiO NPs and < 60 nm for Ni NPs confirmed by X-ray diffraction analysis and Scanning electron microscope (SEM). Functional groups indication was made by using Fourier transform Infrared (FT-IR) spectroscopic analysis of materials. Catalytic efficiency was investigated against methylene blue dye, the maximum degradation efficiency was 98.8%, followed by first order reaction kinetics. Synthesized NPs were highly stable i.e. till 3 months. Biological test results exposed that synthesized Ni and NiO nanoparticles have broad spectrum antibiotic abilities against E. coli and Bacillus subtilus.