A FTIR characterization of surface interactions of cyanide and coppercyanide with a platinum electrode in alkaline solution

Abstract

In this paper, the nature of the species formed in the electrochemical interactions between a polycrystalline platinum surface and cyanide and copper-cyanide species in alkaline solution (pH 13) has been investigated by combining cyclic voltammetry with in situ FTIR spectroscopy. This study was performed because electrochemical reactors for the treatment of cyanide-containing industrial wastewaters have been shown to achieve viable destruction rates when copper ions are present in the alkaline solution through the formation of copper oxide films [1-3]. It has been found that the complexation of cyanide ions by copper species hinders the adsorption of the anion at the electrode, thus avoiding the characteristic electrode poisoning by CO that occurs in the absence of soluble copper species. Conversely, soluble copper-cyanide complexes can be electrooxidized at the platinum surface through the formation of cyanate species as intermediate, and of HCOOH and NO as end products. The addition of copper species to the electrolyte also facilitates this route for cyanide oxidation to occur at higher rates without poisoning the platinum electrode

FTIR

voltammetry

platinum

cyanide oxidation

copper ions

catalysis