Ficus sur mediated synthesis of mesoporous ZnO nanoparticles and novel ZnO/Arginine/Tyrosine nanocomposite as eco‑friendly corrosion inhibitors for mild steel in hydrochloric acid medium.

Abstract Ficus sur-mediated synthesized ZnO nanoparticles (ZnONps) and synthesized ZnO/arginine/tyrosine nanocomposite (ZAT) were characterized using X-ray diffraction (XRD), ultraviolet visible (UV) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) spectroscopy, X-ray fluorescence (XRF), Dynamic light scattering (DLS) and Brunauer-Emmett-Teller (BET) analysis. Corrosion inhibition efficacy of ZnONps and ZAT in 1 M HCl was studied using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), gravimetric analysis and atomic absorption spectroscopy (AAS). XRD analysis revealed that ZnONps and ZAT are crystalline with average crystallite size equal to 28.5723 nm and 32.65 nm respectively. The hydrodynamic size for ZnONps and ZAT were found to be 34.99 d.nm and 36.57 d.nm respectively from DLS analysis. XRF confirmed ZnONps synthesis and corroborated UV-vis, FTIR and EDX results. PDP analysis revealed that ZnONps and ZAT showed mixed-type inhibitor propensity. Corrosion current densities (Icorr) decreased in the presence of ZnONps and ZAT resulting to inhibition efficiency of 92.4 % and 98.5 % respectively in the presence of 1000 ppm of each inhibitor. Charge transfer resistance values decreased in the presence of inhibitors which suggests formation of protection film on mild steel surface. Electrochemical analysis results are in agreement with gravimetric and AAS analysis findings.