Facile Green Synthesis of Undoped ZnO and Copper-Doped Zinc Oxide Nanoparticles using Albizia lebbeck leaf extract: Electrochemical Insights and Anti-Corrosion Potential

This study reports the facile green synthesis of undoped ZnO and copper-doped ZnO (Cu–ZnO) nanoparticles using Albizia lebbeck leaf extract as a reducing and stabilizing agent. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and UV–Vis spectroscopy. XRD analysis confirmed the hexagonal wurtzite structure with average crystallite sizes of 18 nm for undoped ZnO and 12 nm for Cu–ZnO. Electrochemical studies, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), evaluated the anti-corrosive performance on mild steel in 1 M HCl. The results demonstrated a significant increase in corrosion resistance for Cu–ZnO nanoparticles. The corrosion rate for Cu–ZnO coated mild steel was 0.45 mm/year, compared to 1.12 mm/year for undoped ZnO and 2.43 mm/year for the bare sample. The corrosion current density (I_corr) for Cu–ZnO was 0.89 µA/cm², significantly lower than 2.13 µA/cm² for undoped ZnO and 4.67 µA/cm² for the bare sample. SEM images revealed spherical nanoparticles with average diameters of 20–30 nm (undoped ZnO) and 15–25 nm (Cu–ZnO). Additionally, UV–Vis spectroscopy showed a blue shift in the absorption edge from 376 nm (undoped ZnO) to 366 nm (Cu–ZnO), indicating enhanced optical properties. This environmentally friendly method offers a sustainable alternative for nanoparticle synthesis and opens new avenues for corrosion protection applications.