Structurally and morphologically engineered single-pot biogenic synthesis of NiO nanoparticles with enhanced photocatalytic and antimicrobial activities

The cumulative aquatic contamination and contagious diseases in the present modernity are revealing the high demand for many savior revolutionary materials in the future. In this regard, the potential for green synthesis of NiO NPs has been efficiently investigated for future engineering and medical concerns. Authors employ a facile green route for the synthesis of nickel oxide nanoparticles (NiO NPs) using Piper betle leaves extract as a capping and reducing agent. Synthesized NPs have been analysed by several spectroscopic and microscopic techniques, such as UV–visible spectroscopy, Fourier infrared transform (FTIR), X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-rays (EDX), and transmission electron microscopes (TEM). NiO NPs show a redshift in the absorption energy spectrum with a band gap energy of 2.50 eV. The FTIR spectrum confirms the presence of O–H bonds, O = C = O bonds, C–H bonds, N–C bonds and C = C bonds on the surface of the NiO NPs. XRD study reveals the rhombohedral crystal structure of the NiO NPs. Crystallite size is verified by Debye Scherrer, Williamson–Hall and the Modified Debye Scherrer calculations. SEM/EDX shows bunches of particles distributed over a large area with a non-agglomerated state and atomic percentage of the elements. The organic moieties of Piper betle lead to the generation of various shapes of NiO NPs as observed in high magnification TEM images. The synthesized NiO NPs embrace the extraordinary potential for photocatalytic decolorization of the RR141 dye with 99% efficiency and a high dye degradation rate of 0.03161 min−1. Additionally, the synthesized NiO NPs have shown high antimicrobial activity against the E. coli (gram negative) and B. subtilis (gram positive) microorganisms. This work demonstrates an efficient method for employing synthesized NiO as an effective photocatalyst for the degradation of RR141 dye and as a bactericidal agent for gram-positive and gram-negative bacteria.