DFT and experimental investigation of a novel 1,2,4-triazole derivative as a corrosion inhibitor for carbon steel A106 G/B in HCl solution

• R.S. Ahmed¹, F.M. Hussein², N.H. Ali³, I.M.H. Almousawi⁴, L.S. Ahamed⁴, I.Y. Mohammed⁵, E.M. Hussain⁶, F.A. Almalki⁷ and B. Hammouti⁸

¹ Department of Anesthesia Techniques, College of Health and Medical Techniques, Middle Technical University, 10053, Baghdad, Iraq
² Department of Chemistry, College of Science, Mustansiriyah University, Baghdad, 10052, Iraq
³ Scientific Research Commission/Training Department, Baghdad, 10016, Iraq
⁴ Department of Chemistry, College of Science, University of Baghdad, Baghdad, 10070, Iraq
⁵ Department of Bio, College of Science, University of Al-Turath, Baghdad, Iraq
⁶ Department of Chemistry, College of Education for Pure Science (Ibn Al-Haitham), University of Baghdad, Baghdad, Iraq
⁷ Department of Pharmaceutical Sciences, Faculty of Pharmacy, Umm Al-Qura University, Makkah, 21955, Saudi Arabia
⁸ Euromed University of Fes, UEMF, Fes, 30070, Morocco

Abstract: This work introduces a newly synthesized triazole derivative, 5-([(2-furanyl)methyl]-thiomethyl)-4-(naphtha-2-yl)-3-hydroxyl-4H-1,2,4-triazole (FTNT), as an effective corrosion inhibitor for carbon steel A106 G/B in 0.1 M HCl solution. The structure of the novel derivative was confirmed by FTIR, ¹H NMR, and ¹³C NMR spectra. Potentiodynamic polarization measurements reveal that FTNT markedly suppresses corrosion, with inhibition efficiency reaching 81.6% at 600 ppm. Thermodynamic analysis indicates spontaneous, physisorption/chemisorption-augmented adsorption of FTNT on the steel surface, best described by the Freundlich isotherm. Atomic force microscopy (AFM) surface examination demonstrated that a protective FTNT coating precipitated on the metal surface. The experimental findings are corroborated by complementary density functional theory calculations at the B3LYP/6-311++G (d, p) level, which demonstrate advantageous electronic properties and adsorption propensity that are correlated with high inhibitory efficiency. The results provide molecular-level insight into the rational design of triazole-based corrosion inhibitors, and FTNT represents a focused, well-characterized inhibitor with practical potential to reduce carbon steel corrosion in acidic settings.

Keywords: carbon steel A106, corrosion inhibitor, 1,2,4-triazole derivative, potentiodynamic polarization

Int. J. Corros. Scale Inhib., 2026, 15, no. 1, 405-428
doi: 10.17675/2305-6894-2026-15-1-21

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