The inhibition effect of the 2-thioxo-1,2-dihydroquinoline-4-carboxylic (Q2) on carbon steel (CS) corrosion in 1 M HCl have been determined by electrochemical techniques like potentiodynamic polarization (PDP), electrochemical impedance spectroscopy studies (EIS) and weight loss measurements. The experimental results reveal that Q2 is an effective inhibitor with a maximum achievable inhibition efficiency of 95% at 10-3 M. The polarization curves indicated that Q2 behaved as a mixed-type inhibitor while the Nyquist plots revealed that the corrosion was a charge transfer controlled process. Moreover, the absorption of Q2 was found to obey the Langmuir adsorption isotherm. Density functional theory (DFT) was employed for theoretical calculations.
