Detailed experimental and computational explorations of pyran derivatives as corrosion inhibitors for mild steel in 1.0 M HCl : Electrochemical/surface studies, DFT modeling, and MC simulation

The present paper examines the adsorption of two novel heterocyclic compounds of the pyran derivatives, namely 2-amino-5-oxo-4-(p-tolyl)-4H,5H-pyrano [3,2-c]chromene-3-carbonitrile (PY-CH3) et 2-amino-5-oxo-4-phenyl-4H,5H-pyrano [3,2-c]chromene-3-carbonitrile (PY-H)against corrosion of mild steel in molar HCl medium. The experimental investigation was carried out using several techniques including Electro-chemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (PDP). The inhibition efficien-cies of PY-CH3 and PY-H followed the order: 80.0% (PY-CH3) < 90.0% (PY-H). The adsorption process of PY-CH3 and PY-H on the mild steel surface follows Langmuir adsorption model. Surface characterization analysis using Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray analysis (EDS), Atomic Force Microscopy (AFM), X-ray diffraction analysis (XRD), and Infrared Spectroscopy (FT-IR) sup-ported the formation of a barrier layer that covers the mild steel surface. WL measurements were also tested using inductively coupled spectroscopy (ICP) and UV-Vis spectrometry (UV-Vis). The interaction mechanism of PYCH3 and PY-H with mild steel surface and their mode of adsorption were studied using DFT and Monte Carlo (MC) simulations, respectively. (C) 2022 Elsevier B.V. All rights reserved.