Corrosion inhibition of copper in aqueous chloride solution by 1H-1,2,3-triazole and 1,2,4-triazole and their combinations: electrochemical, Raman and theoretical studies.

Triazoles are well-known organic corrosion inhibitors of copper. 1H-1,2,3-Triazole and 1,2,4-triazole, two very simple molecules with the only difference being the positions of the nitrogen atoms in the triazole ring, were studied in this work as corrosion inhibitors of copper in 50 mM NaCl solution using a set of electrochemical and analytical techniques. The results of electrochemical tests indicate that 1H-1,2,3-triazole exhibited superior inhibitor properties but could not suppress anodic copper dissolution at moderate anodic potentials (>+300 mV SCE), while 1,2,4-triazole, although it exhibited higher anodic currents, suppressed anodic copper dissolution at very anodic potentials. Density functional theory calculations were also performed to interpret the measured data and trends observed in the electrochemical studies. The computational studies considered either the inhibitors isolated in the gaseous phase or adsorbed onto Cu(111) surface models. From the calculations, the mechanisms of the inhibitive effects of both triazoles were established and plausible mechanisms of formation of the protective films on the Cu surface were proposed. The results of this study hold positive implications for research in the areas of catalysis, and copper content control in water purification systems.