Surface-enhanced Raman spectra and electrochemical studies on the inhibition of nickel corrosion by imidazole

Surface-enhanced Raman scattering (SERS) spectrum of imidazole adsorbed on a nickel electrode in 0.1 mol . L-1 KCl solution was investigated as a function of applied potential. The corrosion inhibition effects of imidazole on the nickel electrodes in 0.1 mol . L-1 KCl solution were investigated by using both cyclic voltagram and Tafel plot. The results indicated that imidazole was adsorbed on Ni electrode with tilted or perpendicular orientation due to the maximum enhancement of the in-plane vibration modes. The appearance of the peak at 1 173 cm(-1) (i.e. NH deformation) further supported the adsorption of neutral imidazole molecules in a neutral solution. A low-wave number band appeared at 214 cm(-1) was assigned to the Ni-N stretch, considering the interaction between imidazole molecules and the metal surface via N-atom. The molecules had maximum adsorption at -1.3 V. At higher negative potentials, the adsorption decreased gradually, which resulted in weaker inhibition effect.