Theoretical and experimental studies of the corrosion inhibition effect of nitrotetrazolium blue chloride on copper in 0.1 M H2SO4

Abstract

The inhibition effect of nitrotetrazolium blue chloride (NTBC) on copper corrosion in 0.1 M H₂SO₄ solution was investigated by quantum chemical calculations, molecular dynamic (MD) simulations, electrochemical measurements, and scanning electron microscopy (SEM) surface morphological examination. X-ray photoelectron spectroscopy (XPS) measurements were also employed to study the adsorbed layer of NTBC on the copper surface. Adsorption behaviors of NTBC on copper surfaces were studied by MD simulations. The inhibition effect of NTBC was further confirmed by the results of electrochemical measurements and surface morphological examination. The NTBC increased the total resistance of the copper corrosion process according to the results of EIS due to formation of an absorption layer on the copper surface. Potentiodynamic polarization curves indicated that the corrosion rate decreased prominently with the addition of NTBC into H₂SO₄ solution, as the increasing concentration of NTBC caused a decreasing current density (i_corr). The optimal concentration of NTBC as an inhibitor for the corrosion of copper in 0.1 M H₂SO₄ solutions was determined to be 500 ppm according to electrochemical and morphological studies. Quantum chemical calculations were employed to study the electronic properties of NTBC to ascertain the correlation between the inhibitive effect and the molecular structure. Both the experimental and theoretical results are in good agreement with each other in this regard and confirm that NTBC is an effective inhibitor. The quantum chemical calculations and MD simulations provided strong evidence that the superior inhibition effect of NTBC is due to its ability to adsorb strongly at copper surfaces.