Corrosion inhibition and adsorption mechanism of novel imidazopyridine corrosion inhibitors: Electrochemical and computational studies

Abstract

• IPCl3 & IPF3 acted as effective corrosion inhibitors for MS in 1 M HCl environment, reaching 97.4 % & 96.5 % at 0.001 M. • PDP and EIS techniques were performed and showed the high resistance of MS samples. • The surface characterization confirms the thin layer formed by IPCl3 and IPF3. • DFT calculations predict high reactivity performance of IPCl3 and IPF3. • MD simulation predict high interaction with MS samples. The present work investigates the inhibition performance and the adsorption mechanism of two newly synthesized molecules named 6-chloro-2-(4-chlorophenyl) imidazo[1,2-a] pyridin-3-amine (IPCl3) and 6-chloro-2-(4-fluorophenyl) imidazo[1,2-a] pyridin-3-amine (IPF3). These inhibitors were evaluated for their ability to prevent the corrosion of mild steel in a 1 M hydrochloric acid (HCl) medium, using both weight loss measurements and electrochemical techniques. The extracted outcomes proved that IPCl3 and IPF3 compounds acted as effective inhibitors since reaching an inhibition percentage of 97.4 % for IPCl3 and 96.5 % for IPF3 at the optimum concentration of 0.001 M. Based on potentiodynamic polarization experiments, these molecules behaved as mixed-type inhibitors. These molecules can be adsorbed on steel surfaces, following Langmuir Isotherm. Scanning Electron Microscopy coupled with Energy Dispersive X-ray analysis (SEM-EDX) confirms the existence of a preventive layer of IPCl3 and IPF3 on the steel surface. Quantum chemical calculations (Density Functional Theory (DFT) & Molecular Dynamic simulations) were also performed to compare the electronic properties of IPCl3 and IPF3 with the inhibition efficiencies achieved experimentally. They revealed the same deal with the experimental findings.