Enhancing the structural and morphological properties of cerium oxide nanostructures for effective corrosion protection of mild steel

Abstract

The widespread issue of metal corrosion, particularly in harsh environments such as acidic, alkaline, and saline conditions, poses significant challenges to the durability and functionality of materials. Cerium oxide nanoparticles (CeO₂ NPs) have been prepared in this study using a sonication-assisted green synthesis technique with the extract of Nelumbo nucifera leaves serving as a reducing and stabilizing agent. Comprehensive characterization techniques, including XRD, FESEM, HRTEM and DLS are used to investigate the structural phase, crystalline properties, and morphology of the synthesized nanoparticles. The optical properties are analyzed using UV–visible and photoluminescence (PL) spectroscopy, while FTIR identified the functional groups responsible for stabilization. The EIS and potentiodynamic polarization techniques are utilized to evaluate the corrosion behaviour of CeO₂-coated mild steel (MS) plates compared to uncoated MS plates in various electrolytes: 1M HCl, 1M KOH, and 3.5% NaCl. The Nyquist plot revealed the conducting nature of the material, forming a characteristic semicircle indicative of charge transfer resistance. The Tafel plot provided insights into the corrosion activity of coated and uncoated MS plates, while the Bode plot determined the impedance frequency. The CeO₂-coated mild steel plate demonstrated significantly enhanced corrosion resistance under all tested conditions, achieving a maximum corrosion inhibition efficiency of 85% in a 3.5% NaCl medium compared to uncoated MS plates.