Metal-organic frameworks based on silver (I) and nitrogen donors as new corrosion inhibitors for copper in HCl solution

Yellow crystals of the coordination polymers MOF[Ag (qox) NO3], 1 [Ag(pyzca)], 2 were obtained by the reaction of AgNO3 with quinoxaline (qox) or pyrazine carboxylic acid (pyzca). The MOFs 1 and 2 were tested as corrosion inhibitors for copper in 1 M HCl solutions using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Results of the polarization revealed that these coordination polymers are mixed type. Adsorption of the MOFs 1 and 2 was found to obey Langmuir adsorption isotherm. The effect of temperature on the corrosion rate was studied and activation parameters were calculated and discussed. The results obtained from the two different electrochemical techniques are in good agreement.