DFT-guided design and experimental validation of small molecules to fight against mild steel corrosion: Chemical synthesis and extensive evaluation of 4 small enones as corrosion inhibitors

Abstract

Ab initio density functional theory (DFT) and Molecular Dynamics tools were employed to simulate and evaluate the influence of the nature of functional groups in position 4 of ring B in a chalcone moiety while having a fixed electron donating group (EDG) in position number 4 of ring A. The results obtained from these quantum mechanics calculations were then used to select four structures that showed potential to be used as corrosion inhibitors for mild steel in HCl media. The four compounds were prepared using a green chemical synthesis and were subsequently evaluated through a combination of electrochemical techniques, weight loss studies and surface analysis. This experimental approach enabled the assessment of the effectiveness of these inhibitors in mitigating corrosion. Electrochemical measurements demonstrated that the inhibitors significantly increased the charge transfer resistance (Rct) from 70 Ω cm² (blank) to up to 1860 Ω cm², achieving maximum inhibition efficiencies of approximately 96 %. Gravimetric studies further confirmed significant reductions in corrosion rates under all tested conditions. Surface analyses (AFM and SEM) demonstrated smoother steel surfaces in the presence of the inhibitors, confirming the formation of protective adsorbed films. The substantial congruence between computational predictions and empirical data substantiates the effectiveness of integrating theoretical screening with synthetic validation in the development of potent organic corrosion inhibitors for industrial applications. © 2025 Elsevier B.V.