Novel Synthesized Benzothiazole Bearing a Pyrazole Moiety as Corrosion Inhibitor for Copper in 1 M Nitric Acid Solution: Experimental and Theoretical Modeling

In this study, we are looking into how to prevent corrosion of copper in 1 M HNO₃ by synthesizing a novel benzothiazole bearing a pyrazole moiety, namely, 4-(benzo-[<i>d</i>]-thiazol-2-yl)-1<i>H</i>-pyrazol-5-amine (BTPA), which was confirmed by weight loss (WL), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), atomic force microscopy, and FTIR measurements. As the temperature rises, the inhibitory efficacy (IE) falls and grows with an increase in BTPA dosage. At higher inhibitor concentrations, WL data showed improved BTPA adsorption on the copper surface with a maximum effectiveness of 92.5% at 15 μM concentration and 25 °C. The Langmuir isotherm provided the most accurate description of the adsorption of the studied derivatives on the copper surface. The calculated values of the standard free energy change of adsorption (Δ<i>G</i> _ads ^o) and the adsorption equilibrium constant (<i>K</i> _ads) suggested the spontaneous character and exothermic nature of the adsorption phenomenon. The investigated BTPA performs as a mixed-type inhibitor according to the polarization results. The BTPA molecule demonstrated an effective adhesion to the Cu surface, as demonstrated by techniques using atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Computational chemical methods, including quantum chemical and molecular dynamics simulations, yielded relevant results that aligned with the experimental findings. The quantum chemical parameters (<i>E</i> _LUMO, <i>E</i> _HOMO, and Δ<i>E</i>) exhibit a significant correlation with the protective efficacy of the examined BTPA. Monte Carlo (MC) simulations were also used to predict the inhibitor conformational adsorption alteration on the copper surface. Finally, this investigation demonstrated that the experimental and theoretical data had a strong correlation.