Bisquinoline analogs as corrosion inhibitors for carbon steel in acidic electrolyte: Experimental, DFT, and molecular dynamics simulation approaches

The inhibition performance of two bisquinoline analogs, 3-bis((8-hydroxyquinolin-5-yl)methyl)thiourea (BQMT) and O-((8-hydroxyquinolin-5-yl)methyl)((8-hydroxyquinolin-5-yl)methyl)((8-hydroxyquinolin-5-yl)methyl) carbamothioate (QMHC), on carbon steel (CS) in 1M HCl have been assessed through using weight loss tests, electrochemical techniques, scanning electron microscope (SEM), Uv-visible spectroscopy, as well as theoretical calculations. The experimental outcomes exhibited that BQMT and QMHC have largely inhibited the CS corrosion and their inhibition efficiency enhances with the increase of concentration. The maximum inhibition efficiency of BQMT and QMHC was figured out to be 95.0 and 92.3 percent at 10−3M, respectively. Potentiodynamic polarization (PDP) studies exhibited that BQMT and QMHC behave as mixed-type inhibitors. Adsorption of BQMT and QMHC on CS surface is examined by SEM, Uv-visible, and different isotherm models, which obey Langmuir isotherm. Furthermore, Density functional theory (DFT) and molecular dynamics simulation (MDS) calculations were implemented to understand the corrosion resistance mechanism.