Synthesis, electrochemistry, DFT studies and MD simulations of novel dopamine derivatives for corrosion inhibition of Q235 steel in 1 M HCl solution

Novel multisubstituted dopamine derivatives were synthesized and their ability to protect carbon steel in 1 M HCl was investigated by combining electrochemistry , surface analysis and theoretical calculations. The results showed that 91.53% inhibition could be obtained by adding 0.1 g/L of dopamine derivatives at 298 K. Potentiodynamic polarization tests showed that the addition of the dopamine derivative resulted in a corrosion potential difference of ≤ 31 mV, thus identifying the compound as a hybrid inhibitor. X-ray photoelectron spectroscopy and contact angle indicate the successful formation of a hydrophobic barrier on the carbon steel surface, and scanning electron microscopy and laser confocal microscopy confirm the improvement in surface morphology. The dopamine derivatives fit the Langmuir adsorption model with both physical and chemical adsorption. Density functional theory and molecular dynamics simulations revealed that dopamine derivatives rely on lone pairs of electrons in heteroatoms to adsorb parallel to the metal substrate and protect the carbon steel from corrosive media attack. Thus, dopamine derivatives can contribute to the pickling industry as a green corrosion inhibitor to avoid steel damage and waste.