Electrochemical, LC–MS, and computational analysis of Urtica ardens molecules as corrosion inhibitors for stainless steel 410 in an acidic medium

The present research investigates the corrosion inhibition potential of compounds identified through liquid chromatography–mass spectrometry (LC–MS). The major compounds identified were quercetin-3-O-sophoroside, chlorogenic acid, and (E)-N-[2,3-dihydroxy-1-(hydroxymethyl)-7-heptadecenyl]-2-hydroxyceramide. The functional groups, such as hydroxy and carbonyl, present in the compounds were analysed using infrared spectroscopy (IR), and the adsorption behaviour of the compounds was determined through ultraviolet–visible spectroscopy (UV–Vis). Corrosion inhibition efficiency was evaluated using both weight-loss and electrochemical techniques. To assess surface morphology, scanning electron microscopy (SEM) and 3D optical profilometry were employed to compare corroded steel samples with and without the inhibitor. Furthermore, Monte Carlo simulations (MCS) were carried out to evaluate the interaction energies between the inhibitors and the SS-410 surface, while density functional theory (DFT) calculations were used to identify reactive sites and bonding locations within the molecules. The results showed that the inhibition efficiency of Urtica ardens water extract (UAWE) increased with concentration, reaching a maximum of 92.61% at 800 ppm. Out of this total corrosion inhibition, the contributions of chlorogenic acid, a 2-hydroxyceramide derivative, and quercetin-3-O-sophoroside are 24.32, 46.18, and 29.50%, respectively. Additionally, surface analysis using AFM revealed a decrease in the average surface roughness from 560 nm to 57.3, while EDX analysis indicated an increase in the iron content of SS-410 from 37.5 to 62.0% in the presence of the inhibitor, confirming the formation of a stable protective film on the steel surface.