Understanding corrosion inhibition of iron by 2-thiophenecarboxylic acid methyl ester: Electrochemical and computational study

Abstract

The inhibiting effect of 2-thiophenecarboxylic acid methyl ester, TME on iron corrosion in 1.0 M HCl solutions were evaluated using several electrochemical measurements includes potentiodynamic polarization, electrochemical impedance spectroscopy and electrochemical frequency modulation techniques. Adsorption mechanism of TME on iron surface was explored by explicit solvent simulations using molecular dynamics and quantum chemical calculations. Molecular dynamics simulation techniques are used to calculate the adsorption energy as well as the binding energy between the TME molecule and the iron surface. Also, Adsorption density of the inhibitor molecules on iron surface was calculated using Metropolis Monte Carlo method. Experimental investigations of the studied thiophene derivative show that it reduces the corrosion rate of iron remarkably as its concentration increases. Polarization studies show that TME molecules act as cathodic-type inhibitor. The presence of sulphur and oxygen atoms as well as π-electrons enables the interaction and bonding between TME and the iron surface. © 2012 by ESG.