Corrosion inhibition of copper particles on ITO with 1,2,4-triazole-3-carboxylic acid

Copper particles electrodeposited on ITO/glass (Cu/ITO) have been prepared and used to explore the inhibitory capability of 1,2,4-triazole-3-carboxylic acid (TCA) against the copper oxidation. The protective effect of TCA for the Cu/ITO is demonstrated in CH3OH solution with NaOH and in H2O solution with NaCl, using cyclic voltammetry. The surface species responsible for the corrosion inhibition are analyzed using X-ray photoelectron and infrared spectroscopies. The spectroscopic results strongly suggest that the doubly dehydrogenated TCA (TCA-2H), from the N-H and O-H bond scission, plays an important role for the copper protection. The density-functional-theory calculations of the TCA-2H on Cu(100) and Cu(111) model surfaces show that it is adsorbed with a perpendicular orientation, via the N-1, N-2 and one of the carboxylate oxygens. Moreover, the calculated vibrational frequencies of the TCA-2H on Cu(100) agree with the observed ones from the species exerting the inhibitory effect.