A new benzodiazepine derivative as a highly effective corrosion inhibitor for E24 steel in acidic media: integrated experimental and computational investigations

This study examined a new benzodiazepine derivative (BZ-NO2) as a corrosion inhibitor for E24 steel in a 1 M HCl solution using a combination of experiments and theory. FT-IR,1H NMR, 13C NMR, and ESI+ mass spectrometry techniques were used to learn more about the structure. Gravimetric (weight loss) tests showed that the compound's maximum inhibitory efficiency was 92.86% at 1 mM after 24 hours of immersion. This confirmed that the compound is highly protective. Electrochemical tests (PDP and EIS) showed that BZ-NO2 acts as a mixed-type inhibitor, reducing the corrosion current density (icorr) and increasing the polarization resistance (Rp) as the BZ-NO2 concentration increases. The adsorption mechanism was found to follow the Langmuir isotherm, meaning that the steel surface was covered with a single layer of molecules and that these molecules interacted strongly with the steel surface. Monte Carlo simulations also showed that BZ-NO₂ molecules align parallel to the steel surface, giving them optimal coverage and stability. SEM/EDX tests confirm these results by showing that a homogeneous protective coating has formed. The combination of experimental and computational data shows that BZ-NO2 could be a highly effective and stable corrosion inhibitor for use in industrial environments subject to harsh acidic conditions