Enhanced corrosion inhibition of carbon steel in HCl solution by a newly synthesized hydrazone derivative: Mechanism exploration from electrochemical, XPS, and computational studies

The corrosion inhibition properties of a synthesized hydrazone derivative namely, 1-(4-isopropyl phenyl) -2- (2,4-dinitrophenyl) (HYD (iso)) on API 5L-X60 carbon steel (CS) in 1.0 M HCl solution were evaluated by chemical, electrochemical, X-ray photoelectron spectroscopy (XPS) and theoretical studies. The obtained results revealed that the tested compound acted as a good corrosion inhibitor with inhibition efficiency of 96.32% at a concentration of 5 × 10−3 M. The polarization technique indicated that the HYD (iso) belonged to mixed-type inhibitors, preventing simultaneously anodic and cathodic reactions. The binding between the HYD (iso)'s molecule and CS surface follows a Langmuir adsorption type model and its inhibition mechanism is assisted by physical and chemical interactions. Scanning electron microscope (SEM) and contact angle analyses were performed to examine the surface morphology of inhibited and uninhibited samples. Additionally, theoretical studies using Density Functional Theory (DFT) and molecular dynamics (MD) simulation were performed to explore the most reactive sites of the hydrazone molecule and its adsorption mechanism. [Display omitted] •New synthetized hydrazone derivative acted as an efficient corrosion inhibitor.•NO2 groups are the most basic active site.•XPS results confirmed the formation of an oxoiron (IV) complex.•The hydrazone derivative acted as mixed type inhibitor.•MD simulation confirms the adsorption of the hydrazone on the metal surface.