N-(4-(1,3-benzothiazol-2-ylcarbamoyl)phenyl)isonicotinamide as corrosion mitigator for mild steel in 1 M HCl: A multifaceted study integrating synthesis, characterization, and molecular modelling.

[Display omitted] • BIA reaches 90.40 % efficiency in 1 M HCl on mild steel at 100 ppm and 303 K. • Inhibitor is mixed-type and adsorbs via physiochemical follows Langmuir isotherm. • SEM, EDX, and AFM confirm the inhibitor film formation on mild steel. • DFT reveals the inhibitor interacts with the mild steel surface. • MD simulations and RDF align with experimental results on chemisorption. Newly synthesized, cost-effective corrosion inhibitor, N-(4-(1,3-benzothiazol-2-ylcarbamoyl)phenyl)isonicotinamide (BIA) was evaluated for mild steel/1M HCl interface. BIA showed a maximum inhibition efficiency of 90.40 % at 100 ppm and 303 ± 1 K, with efficiency increasing with concentration but decreasing with temperature. Inhibitor's adsorption followed Langmuir isotherm via physicochemical interactions. Activation parameters revealed BIA retards both metal dissolution and hydrogen evolution held in unimolecular process. Potentiodynamic polarization (PDP) divulged BIA as a mixed-type, impeding charge-transfer. Electrochemical impedance spectra (EIS) confirmed BIA forms a protective double layer, blocking active sites at the interface. Surface analysis supported a protective film formation. Global and local reactivity descriptors using DFT/B3LYP/6-311G++(d,p) were calculated to relate inhibition efficiency with BIA's electronic properties. Molecular dynamics simulation (MDS) showed an interaction energy of −224.7 kJ/mol between BIA and Fe(1 1 0) at 303 K, with Radial Distribution Function (RDF) showing bond lengths under 3.5 Å, confirming a chemical interaction. Theoretical results align with experimental data. [ABSTRACT FROM AUTHOR]