Density Functional Theory of Mild Steel Corrosion in Acidic Media Using Dyes as Inhibitor: Adsorption onto Fe(110) from Gas Phase

Abstract

Quantum chemical calculations based on density functional theory (DFT) methods were performed on indigo blue (IB), methylene blue (MB), and crystal violet (CV) molecules as inhibitors for iron corrosion in acid media. DFT calculations were performed on the molecular structures to describe electronic parameters which are associated with inhibition efficiency such as the Homo values −4.981 eV, −4.518 eV, and −3.872 eV which increased in the order IB > MB > CV while LUMO values were −3.73 eV, −3.63 eV, and −2.87 eV for IB, MB, and CV, respectively. Quench molecular dynamics simulations performed at metal/vacuum interface were applied to find the equilibrium adsorption configurations and calculate the minima interaction energy between inhibitor molecules and iron surface Fe(110). The theoretical order of inhibition efficiency of these dye molecules had a linear relationship with experimentally observed inhibition efficiency on iron corrosion in acid media. The electronic structures as well as reactivity elucidate parameters which could be practical in designing novel high-efficiency, cheap, and eco-friendly inhibitors by quantitative structure-activity relationship (QSAR) method.

DFT and QSAR study of corrosion inhibition on 3,5-di-substituted pyrazole derivatives with heteroatom on position one

“…This implies that DAPT/PHT with highest/lowest EHOMO value should have the highest/lowest tendency to donate its electrons to the metal surface, thereby strongly/weakly bind to the metal surface. However he trend in the EHOMO values of these compounds does not agree completely with the trend in the inhibition efficiencies of the compounds (Oguike, et al, 2013;Semire, et al, 2013).…”

DFT-QSAR studies on corrosion inhibition efficiency of derivatives of thiadiazole, oxadiazole and triazole

“…This implies that DAPT/PHT with highest/lowest E HOMO value should have the highest/lowest tendency to donate its electrons to the metal surface, thereby strongly/weakly bind to the metal surface. However the trend in the E HOMO values of these compounds does not agree completely with the trend in the inhibition efficiencies of the compounds [37,38].…”

Computational Stimulation and Experimental Study on Corrosion Inhibition Qualities of <i>Emilia sonchifolia</i> Leaf Extract for Copper (CU131729) in Hydrochloric Acid

“…A density mixing charge of 0.2 was applied to the orbital occupation to speed up convergence alongside convergence tolerance maximum force of 0.002 Ha/A. Molecular dynamics stimulation was used to replicate interfacial interaction between single ES leaf constituent molecule and Cu(110) crystal using Forcite Quench at COMPASS forcefield while our stimulation parameters were set as reported in our earlier work [26]. The interaction energy (E Bind ), global hardness and softness, electrophilicity and number of transferred electrons were calculated as reported in our earlier work [26].…”

“…Molecular structures of ES leaf constituents and snapshots of side and top view of the lowest energy adsorption minima for single inhibitor molecule simulated on Cu(110) surface. Electron rich centers are known to enhance electrostatic interaction with material surface so also, the presence of p-π conjugation system at the oxygen atoms resulted in a dissociative adsorption which is favourable to crack intramolecular bond of the adsorbate crystal[26]. Furthermore, oxy-groups are usually known to hydrolyze in acidic/near neutral solution and are suitable to displace water molecules at the metal surface which favours corrosion inhibition R. S. Oguike et al…”