Biosynthesized zinc oxide nanoparticles using seed and bark extract of Azadirachta indica for antibacterial, photocatalytic and supercapacitor applications

Abstract

We have reported biosynthesis of zinc oxide (ZnO) nanoparticles (NPs: S3/B3) using an aqueous extract of seeds and barks of Azadirachta indica for antibacterial, photocatalytic, and supercapacitor applications. XRD pattern demonstrates a hexagonal wurtzite structure while FTIR spectra confirm the phytochemicals coating. Morphology is revealed from the FE-SEM images: (a) block-shaped S3 with ∼ 50–100 nm width and 90–125 nm length; (b) bar-shaped B3 with ∼ 40–50 nm thickness and 200 nm length. DLS study showed a zeta potential value of −28.93/-28.00 mV for S3/B3 indicating their good colloidal stability in aqueous suspension. Besides, antimicrobial activity of S3 is performed on various gram-negative/-positive bacteria and minimum inhibitory concentrations (MIC) are determined as 125–150 μg/mL. Moreover, methyl orange dye has been degraded with B3 NPs with a degradation efficiency of 84.62% in 180 min. Furthermore, the specific capacitance (Cs) and energy density (E) values of the S3/B3 confirmed their potentiality for supercapacitor applications.