The application of 2-(3-nitrophenyl)imidazo[1,2-α]pyridine as an effective corrosion-defender for steel in acidic environment

Abstract

Metal corrosion in acidic settings presents serious problems for many industrial areas. The creation of corrosion inhibitors that are efficient, long-lasting, and ecologically benign is essential. This study introduces a novel corrosion inhibitor, 2-(3-nitrophenyl)imidazo[1,2-α]pyridine (NIP), which was synthesized for protecting mild steel in 1 M HCl. The synthesized NIP was evaluated using Electrochemical Impedance Spectroscopy (EIS), Potentio-dynamic Polarization (PDP), Scanning electron microscopy (SEM), Energy X-ray analysis (EDX), and theoretical approache, including Density Functional Theory (DFT) and Monte Carlo simulations (MCs). NIP demonstrated outstanding protection behavior, reaching a peak of 91.47 % at a concentration of 1.00 mM. PDP studies classified NIP as a mixed-type inhibitor that effectively mitigated both anodic and cathodic reactions. SEM and EDX analysis confirmed the formation of a protective layer on the surface of the structural steels, composed mainly of nitrogen and oxides, indicating the presence of the inhibiting agent. DFT calculations identified the imidazole ring and heteroatoms (N and O) as the active sites for corrosion inhibition. The adsorption behavior of NIP on the metal surface has been studied by means of Monte Carlo simulations. The inhibitory efficiency of NIP was evaluated across a temperature range of 298–323 K, and the results showed a decrease in efficacy with increasing temperature, which provides crucial information for practical applications. The Langmuir model fit indicated a mixed mode of physical and chemical adsorption, with a calculated ΔG°ads value of −33.76 kJ/mol. This novel approach pinpointed reactive sites within the NIP, enhancing our understanding of its protective mechanism at the molecular level.