Rosmarinus officinalis l. Oil as an Eco-Friendly corrosion inhibitor for mild steel in acidic Solution: Experimental and computational studies

In this research, Rosmarinus officinalis L. (ROL) essential oil extracted from the plant was initially introduced as a green anti-corrosion agent for mild steel (MS) in a 1 M HCl solution. The components of the extract were identified using gas chromatography-mass spectrometry (GC–MS) and UV–Vis method. Gravimetric and electrochemical techniques (EIS and PDP) demonstrated that ROL inhibited steel corrosion by 90 % at a concentration of 1.5 g/l. The PDP experiment indicated that ROL essential oil acted as a mixed-type inhibitor with a cathodic predominance. The morphological and elemental characteristics of the metal surface were examined using SEM and EDX, revealing the formation of a corrosion-resistant film on the metal surface. The inhibited corrosive solutions were characterised before and after immersing MS using UV–visible spectrophotometry, indicating the possibility of iron-ROL complex formation. Finally, theoretical calculations using DFT, MC, and MD simulations were conducted and correlated with experimental results.