Catalytic electrodeposition of silver on glassy carbon electrodes modified with films of cobalt phthalocyanine

Glassy carbon electrodes were modified with thin films of unsubstituted cobalt phthalocyanine (CoPc), prepared at the surface of an aqueous NaOH solution by spreading a CoPc solution in CCl3COOH + CHCl3. This simple procedure allows a reproducible and homogeneous modification of the electrodes with a film thickness of the order of a monolayer. Cyclic voltammetry of the modified electrodes and UV-visible spectroscopy of the film and spreading solution is provided. Furthermore, silver electrodeposition on modified and unmodified glassy carbon electrodes from low-concentrated silver solutions in NaCl was studied, using relatively long deposition times up to 100 a at an overpotential of -0.3 V. The charge corresponding to the deposited silver was measured by anodic linear sweep voltammetry. Far both electrodes, linear plots of Q(2/3) vs. t were obtained, which is according to an instantaneous nucleation and three-dimensional growth mechanism. (C) 1997 Elsevier Science S.A.