Phyto-mediated facile synthesis of ZnO nanoparticles: enhanced photocatalysis, biological, and electrochemical properties

In the present work, zinc oxide nanoparticles (ZnO NPs) were prepared via a simple and eco-friendly combustion method employing Cleome gynandra seed extract as a fuel. The synthesized ZnO NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray studies (EDX), Fourier-transform infrared spectroscopy (IR), Raman spectroscopy, and UV spectroscopy (UV–Vis). XRD confirmed the crystalline nature of the material with a hexagonal wurtzite structure having an average crystallite size of 28 nm. SEM images confirm the formation of spherical with agglomerated forms of ZnO NPs. FTIR spectrum shows the band at 580 cm⁻¹ due to the vibrational mode of Zn–O bending. The band gap of the ZnO was found to be 3.00 eV. Photocatalytic activity of ZnO NPs was assessed using methylene blue (MB) dye under UV light irradiation, demonstrating an admirable 94% degradation around 120 min. The electrochemical studies of the ZnO-modified carbon paste electrode exhibit superior oxidation and reduction potential and also show promising electrode material for H₂O₂ and ascorbic acid sensors. Further, these NPs also exhibit antioxidant and antimicrobial properties and are biocompatible with lymphocytes. Therefore, the synthesized material has good photocatalytic, electrochemical, antibacterial, and antimicrobial properties.