Corrosion inhibition evaluation of Bauhinia purpurea extract mediated ZnO nanoparticles for carbon steel in acidic environment.

ZnO-NPs were synthesised using Bauhinia purpurea leaves and explored as green nano corrosion inhibitors for carbon steel in 1M hydrochloric acid. Comprehensive characterization of the synthesized ZnO-NPs was characterized using Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Electrochemical methods, including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), were performed to evaluate the corrosion inhibition efficiency at varying nanoparticle concentrations. Surface analyses through SEM, XPS, FTIR, and EDS confirmed the ZnO-NPs adsorption on the CS surface, validating the proposed inhibition mechanism. ZnO-NPs synthesized by sol-gel and co-precipitation methods exhibited maximum inhibition efficiencies of 94% and 97% at 100 ppm and 303 K, respectively, as determined by PDP. Consistently, EIS analysis demonstrated superior inhibition performance, with efficiencies of 99% (co-precipitation) and 98% (sol-gel) at 100 ppm. The findings confirm that green-synthesised ZnO-NPs act as effective, eco-friendly inhibitors by forming a protective adsorbed layer on the steel surface, thereby mitigating acid-induced corrosion.