Insight into anti-corrosion mechanism of tetrazole derivatives for X80 steel in 0.5 M H2SO4 medium: Combined experimental and theoretical researches

5-Mercapto-1-methyl tetrazole (MML), 1-12-(dimethylamino)ethyl]-1H-tetrazole-5-thiol (DET), and 1-(4hydroxyphenyl)-1H-tetrazole-5-thiol (HHT) as corrosion inhibitors were studied by electrochemical methods, surface morphology analysis, and theoretical calculations for X80 in acidic medium. Electrochemical impedance spectroscopy data indicate that the corrosion inhibition efficiency for X80 steel in 0.5 M sulfuric acid solution are all greater than 95% when the concentration of HHT, DET and MML is 10 mM at 298 K. The potentiodynamic polarization curve results indicate that HHT, DET and MML are mixed-type corrosion inhibitors. AFM and SEM results are consistent with electrochemical tests. In addition, their adsorption on the X80 steel surface is consistent with Langmuir single-layer isotherm adsorption. Quantum chemical calculations and molecular dynamics simulations are highly consistent with the experimental results. (C) 2020 Elsevier B.V. All rights reserved.