An electrochemical and in situ SERS study of Cu electrodeposition from acidic sulphate solutions in the presence of 3-diethylamino-7-(4-dimethylaminophenylazo)-5-phenylphenazinium chloride (Janus Green B)

This paper deals with the behaviour of 3-diethylamino-7-(4-dimethylaminophenylazo)-5-phenylphenazinium chloride (Janus Green B, JGB) during Cu electrodeposition from an acidic sulphate solution. This investigation was carried out by cyclic voltammetry and in situ Surface Enhanced Raman spectroelectrochemistry. Parameters describing nucleation, charge-transfer kinetics, mass-transport effects and anodic stripping behaviour were derived by quantitative analysis of the cyclic voltammograms. JGB effects have been found on nucleation rate, exchange current density and cathodic Tafel slopes. Voltammetry highlighted the cathodic reactivity of JGB. In situ SERS spectra were measured under both cathodic and anodic polarisation, in the range 0.2-0.7 V vs Ag/AgCl. SERS spectra were recorded also in the galvanostatic mode. SERS effect variations with potential and potentiostatic polarisation time were studied.