An investigation of benzothiazole ionic compound as corrosion inhibitor for carbon steel in acidic media using electrochemical research, surface techniques, DFT, and MD simulation studies

A benzothiazole-based compound, namely (E)-3-ethyl-2-(2-fluorostyryl)benzo[d]thiazol-3-ium iodide, was investigated as a corrosion inhibitor of carbon steel in an acidic solution. Electrochemical studies, atomic force microscopy (AFM), UV–visible spectroscopy, and scanning electron microscopy (SEM-EDX) were used to investigate the surface shape and composition of the BTFI film. In addition, molecular dynamics simulation (MD) and density functional theory (DFT) calculations were used to predict the adsorption structures of the molecules on the steel surfaces. The results show that the inhibition performance (η%) increases with increasing concentration of BTFI, reaching a maximum value of 97.9 % at a concentration of 10⁻³ M. Furthermore, the results of the potentiodynamic polarization test showed that BTFI had an effect on both cathodic and anodic processes. According to the Langmuir model, the inhibitors formed protective layers by adsorption on the metal surface. In addition, surface studies showed that the BTFI-protected HCl medium could reduce roughness and prevent surface damage. The electrical and adsorption properties of the benzothiazole derivative were described by DFT calculations and MD simulations. The experimental results were validated by the recordings of both methods.