Investigating the effectiveness of an imidazopyridine-based compound as an anti-corrosive additive for mild steel in molar hydrochloric acid solutions: a mutual multi-facet experimental and computational approach

Abstract

The use of effective, environmentally friendly inhibitors is a promising strategy to mitigate metallic corrosion. This work involved the development of a new imidazopyridine-based compound (i.e., MPPIP) and an assessment of its effectiveness as an anti-corrosive entity for the mild steel metal (MS) in 1.00 M hydrochloric acid medium. The compound's performance was evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), which demonstrated that MPPIP achieves 98% inhibition efficiency with 10⁻³ M concentration at room temperature. The electrochemical analysis confirmed that MPPIP acts as a mixed-type inhibitor, reducing both anodic and cathodic reactions. Thermodynamic analyses revealed that MPPIP adsorption follows Langmuir's isotherm, involving a combination of physisorption and chemisorption mechanisms. Additional validation was performed using UV-Vis spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), which revealed a uniform protective film on the steel surface, preventing metal dissolution. Computational approaches, including density functional theory (DFT) and Monte Carlo simulations, highlighted the molecule's high electron-donating ability and strong adsorption energy, confirming its strong interaction with the metal surface. These findings demonstrate that MPPIP is a promising and efficient corrosion inhibitor for mild steel in acidic environments with inexpensive and easily synthesized route characteristics.