Green approach to corrosion inhibition of 304 stainless steel in hydrochloric acid solution by the extract of Salvia officinalis leaves

Highlights: ► Salvia officinalis extract was examined as a corrosion inhibitor for steel. ► The inhibition efficiency increases with the increasing of extract concentration. ► Adsorption of S. officinalis extract on stainless steel surface is spontaneous. ► Activation energy decreases with addition of S. officinalis extract. - Abstract: The extract of Salvia officinalis (S. officinalis) leaves has been evaluated as a corrosion inhibitor for 304 stainless steel in 1 M HCl solution by means of weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Tafel polarization study revealed that extract of S. officinalis acts as a mixed type inhibitor. Adsorption of the inhibitor on the steel surface followed Langmuir adsorption isotherm. Quantum chemical calculations using the density functional theory (DFT) and semi-empirical method (AM1) were performed to illustrate the process of adsorption of some specific components of the extract.