1,2,4-triazole-5-thione derivative for inhibiting carbon steel corrosion in 1M HCl: Synthesis, electrochemical, SEM/EDX, DFT, and MD investigations

In the current research, the corrosion inhibition efficiency of a novel synthesized 1,2,4-triazole-5-thione derivative, named 1,8bis(5-mercapto-3-(4‑chloro)-phenyl-1,2,4-triazolyl)-triethyleneglycol (3) for carbon steel in 1 M HCl medium is assessed employing conventional weight-loss measurements as well as electrochemical methods, including electrochemical impedance spectroscopy and potentiodynamic polarization. The findings highlighted that the presence of the tested inhibitor led to a decrease in the corrosion rate and enhancement of the inhibitory efficacy with a maximum value of around 93 % obtained at a concentration of 10^–3 M. This might be associated with the creation of a protective adsorption film on the metal surface. Electrochemical measurements disclosed the mixed-type inhibition effect of 3. The inhibitor adsorption mechanism followed the Langmuir adsorption isotherm. Despite that, a thorough examination of the carbon steel surfaces, both in their uninhibited and inhibited states, was conducted through scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) analysis. The experimental findings were supported by computational chemistry calculations using density function theory (DFT) and Molecular Dynamic (MD) simulations.