Detailed DFT/MD simulation, surface analysis and electrochemical computer explorations of aldehyde derivatives for mild steel in 1.0 M HCl

Corrosion prevention in mild steel (MS) is a major issue in the industry. The development of an effective protection strategy is a popular research area. In this work, two molecules, namely methoxy cinnamaldehyde (MCA) and methyl cinnamaldehyde (MeCA) were evaluated as corrosion inhibitors for mild steel in 1.0 M HCl solution, providing a strong basis for the development of new inhibitors platform in the field of corrosion. The corrosion inhibition performance of MCA and MeCA has been studied by using weight loss, Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis, quantum chemical calculations and molecular dynamics (MD) simulation. Results showed that inhibition effectiveness of MCA and MeCA increases with their concentration. Polarization results showed that MCA and MeCA displayed mixed type behaviour. Inhibition efficiencies of MCA and MeCA followed the order: 88% (MCA) < 74% (MeCA). MeCA and MCA inhibit corrosion by adsorbing on MS surface and their adsorption mode followed Langmuir adsorption isotherm via physico-chemical adsorption. SEM/EDX observations of the electrode surface confirm the formation of a film on the metal surface. Theoretical calculations obtained from DFT and Molecular Dynamics (MD) simulation were used to investigate the correlation between the molecular structure of inhibitors and their corrosion inhibition performances, which agree well with the experimental results.

Automated summary

The study evaluated the performance of MCA and MeCA as corrosion inhibitors for mild steel, finding that their inhibition effectiveness increases with concentration and exhibits mixed-type behavior. These inhibitors inhibit corrosion by adsorbing on the metal surface and follow Langmuir adsorption isotherm during the adsorption process.