Green synthesis, electrochemical, and DFT studies on the corrosion inhibition of steel by some novel triazole Schiff base derivatives in hydrochloric acid solution

In this work, three triazole Schiff base derivatives 1-((1H-1,2,4-triazol-3-ylimino)methyl)naphthalen-2-ol (TMN), N-(furan-2-ylmethylene)-1H-1,2,4-triazol-3-amine (FTA) and N-(thiophen-2-ylmethylene)-1H-1,2,4-triazol-3-amine (TTA) were synthesized under ultrasonic irradiation and were investigated as corrosion inhibitors. FT-IR, NMR, and elemental analysis were used to elucidate the chemical structure of the synthesized inhibitors. The inhibitive characteristics of these inhibitors on C-steel corrosion in 1.0 M HCl were studied using three different techniques. The applied techniques were Electrochemical frequency modulation, electrochemical impedance spectroscopy, and potentiodynamic polarization curves. The acquired data from the experimental methods showed that the optimal concentration for TMN, FTA, and TTA is 1.0 × 10−3 mol/L, and the inhibition efficiency reached up to 91.68%, 88.44%, and 87.29% for TMN, TTA, and FTA, respectively. Experiments also indicated that these compounds act as mixed-type inhibitors, and their concentration affects the inhibition efficiency in a directly proportional manner. Quantum paraments obtained from density functional theory (DFT) showed good agreement between experimental and computational results.