Corrosion Inhibition of Carbon Steel in Acidic Environments: Mechanistic Insights and Protective Effects of Triazole-Pyrazole Derivative Inhibitors

Two triazole-pyrazole hybrids, namely ethyl 2-(3-(3,5-dimethyl-1H-pyrazol-1-yl)-1H-1,2,4-triazol-1-yl)acetate (TzPzAcEt) and 2-(3-(3,5-dimethyl-1H-pyrazol-1-yl)-1H-1,2,4-triazol-1-yl)acetic acid (TzPzAcid), were examined for their corrosion inhibition effects on carbon steel in 1 M HCl through electrochemical methods, surface analysis, electrolyte analysis, and molecular modeling. The results indicate that TzPzAcEt and TzPzAcid demonstrate exceptional anticorrosion efficacy, achieving maximum efficiencies of 94.4 and 91.3% at a concentration of 10–3M at the analyzed temperature and concentration circumstances. Triazole-pyrazole hybrids function as mixed-type inhibitors based on polarization assessments. The adsorption of triazole-pyrazole hybrids on the steel surface adhered to the Langmuir isotherm, signifying chemical interactions. In addition, kinetic and thermodynamic characteristics were identified and studied. While scanning electron microscopy (SEM) images reveal no damage following the adsorption of the analogs in the corrosive electrolyte, X-ray photoelectron spectroscopy (XPS) analysis demonstrates the chemical adsorption of the triazole-pyrazole hybrids onto the steel surface. Ultraviolet–visible (UV–vis) spectra confirm the presence of chemical interactions between the triazole-pyrazole molecules and the carbon steel. Finally, the experimental results are supported by density functional theory (DFT) and molecular dynamics (MD) calculations and molecular dynamics simulations, which enhance our understanding of the inhibition processes.