Studying the Urtica dioica leaves extract inhibition effect on the mild steel corrosion in 1 M HCl solution: Complementary experimental, ab initio quantum mechanics, Monte Carlo and molecular dynamics studies

The effectiveness of the Urtica dioica leaves toward mild steel corrosion inhibition in 1 M HCl solution was studied by electrochemical impedance spectroscopy (EIS), polarization test, scanning electron microscope (SEM), atomic force microscope (AFM) and computational approaches. Results revealed that the extract of Urtica dioica showed mixed inhibition effect and its adsorption on the mild steel surface obeyed a Langmuir adsorption isotherm. In addition, a high corrosion inhibition efficiency of 92% was obtained for this inhibitor after 2 h immersion. This inhibitor also yielded high inhibition power even after a long immersion time (24 h), indicating the higher effectiveness of Urtica dioica compared with those reported in literature. It was observed that the corrosion rate of steel in 1 M HCl solution remarkably decreased in the presence of Urtica dioica extract. The computational results elucidated from the Monte Carlo and molecular dynamics simulations evidenced the adsorption of green inhibitors on the steel substrate. Furthermore, the density functional theory calculations suggested the inhibitors adsorption via electronic donor-acceptor interactions.