Assessing the protective efficiency of 5,5′-bis-1,3-benzodioxole against corrosion of XC48 carbon steel: A comprehensive experimental and multi-level computational investigation

The persistent degradation of carbon steel in acidic environments remains a major obstacle across industrial applications, emphasizing the demand for inhibitors that offer both reliability and molecular precision. In this study, we explore the inhibition performance of 5,5'-bis-1,3-benzodioxole (BD) on XC48 carbon steel immersed in 1 M HCl, employing a synergistic framework that combines electrochemical experimentation and multiscale theoretical modeling. Gravimetric analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy confirmed that BD substantially reduces corrosion rates, achieving a peak efficiency of 92.81% at 5 × 10⁻³ M. However, the inhibition effect diminishes with increasing temperature, suggesting a temperature-sensitive adsorption process. The inhibitor's surface binding behavior was best described by Langmuir adsorption isotherms, while polarization studies revealed its mixed-mode character, with a dominant cathodic influence. Surface investigations, including UV–Vis spectroscopy, atomic force microscopy, and optical imaging, revealed a well-formed protective layer consistent with efficient surface passivation. At the molecular level, density functional theory (DFT) and molecular dynamics simulations elucidated BD’s electronic reactivity and favored adsorption geometries. Density functional tight-binding (DFTB) calculations further unveiled strong chemisorptive interactions with the iron surface, including multiple Fe–C and Fe–O bonds. Together, the integration of surface-sensitive experiments and atomistic simulations provides compelling evidence for BD’s viability as a highly effective corrosion inhibitor under acidic conditions. • BD achieves 92.81% corrosion inhibition efficiency for XC48 steel in acidic medium. • DFT and DFTB analyses reveal significant Fe–C and Fe–O covalent adsorption bonds. • MD simulations demonstrate stable and energetically favorable BD-Fe(110) adsorption. • EIS and AFM validate the robust protective film formation by BD on steel surfaces.