Ergel, BusraYildiz, ResitArslanhan, SelimBaran, Mehmet Firat2026-01-152026-01-1520260169-43321873-5584https://doi.org/10.1016/j.apsusc.2025.165587https://hdl.handle.net/20.500.12514/10147Considering the economic and environmental conditions, corrosion appears to be a significant handicap. In this study, anti-corrosion performance of Erodium cicutarium (L.) (EC) is explored in a 1.0 M HCl using potentiaodynamic polarization (PDP), electrochemical impedance (EIS) and linear polarization resistance (LPR) spectroscopies along with morphological, structural and quantum chemical methods. FT-IR and LC-ESI-MS/MS reveal the chlorogenic acid, gentisic acid, protocatechuic acid, vanillin and salicylic acid, containing-C=O, C=C, C-H, C-H, -OH, and aromatic ring. PDP, EIS and LPR showed that at the highest concentration of the EC extract (1000 ppm), the polarization resistance and corrosion current density are measured as 974 Omega cm2 and 246 mu A cm-2, while the inhibition efficiency was found to be 98 %. Inhibition efficiencies decreased with increasing temperature and exposure times due to desorption of adsorbed inhibitor molecules from the surface. But, a notable increase in the Ea value (67.2 kJ mol-1) is observed, thereby hindering the corrosion process. While adsorption behavior is in accordance with the Langmuir isotherm, the Delta G degrees ads (-27.34 kJ mol-1) value indicates both physical and chemical adsorptions. To better understand the inhibitory mechanism, zero charge potential is determined, and quantum chemical calculations of the EC extract's components are performed.en10.1016/j.apsusc.2025.165587info:eu-repo/semantics/closedAccessErodium Cicutarium ExtractCorrosion InhibitorGreen InhibitorMild SteelAdsorptionQuantum Chemical CalculationsArticle2-s2.0-105024751756