Theoretical and electrochemical analysis on inhibition effect of benzotriazole and 1,2,4-triazole on cobalt surface

In this study, the corrosion inhibition effects of benzotriazole (BTA) and 1,2,4-triazole (TAZ) at molecular level were evaluated by quantum chemical method. Density Functional Theory (DFT) at BLYP/3.5DNP level and Monte Carlo simulation were performed to analyze the adsorption mechanism of inhibitors on cobalt surface. The electronic parameters of BTA and TAZ were calculated, and their inhibitory effects were investigated by chemical reactivity parameters, respectively. The reactive centers were analyzed based on Fukui functions, indicating that the N atoms are the coordination sites of the inhibitors. Besides, atom densities of different crystal orientations of cobalt were calculated, and the densest Co (111) surface was selected by Monte Carlo simulations for calculation. Under the circumstance of gaseous and aqueous phases, the adsorption models of BTA and TAZ were established. Also, the interaction energy between inhibitors and cobalt was calculated. The results of potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS) are consistent with the theoretical calculations. The inhibitory effect of BTA on cobalt surface is greater than that of TAZ. This information helps to gain further insight about corrosion system.