COPPER SELENOCYANATE FORMATION ON THE COPPER ANODE

The formation of CuSeCN on a copper anode was studied in 0.1 and 0.5 m ol dm(-3) KSeCN solutions. A thin film of polycrystalline CuSeCN was p roduced with a midpoint potential between the anodic and cathodic peak s for 0.1 mol dm(-3) KSeCN at -0.253 V, close to the open-circuit pote ntial of -0.249 V. A precursory anodic peak or shoulder was seen at ab out -0.210 V, and was ascribed to the formation of a primary (barrier) film. The anodic peak currents for the primary film were linearly dep endent upon the sweep rate. Potential steps into the primary film regi on produced current transients, with the current decaying in proportio n to the reciprocal of time. The anodic peak current and potential for the secondary polycrystalline film were proportional to the square ro ot of the sweep rate, an effect which is consistent with a model for p orous film growth controlled by the resistance across the underlying b arrier film. A weak Raman band due to Se-bonded CuSeCN at 2164 cm(-1) was also observed in situ.