Electrochemical investigations of the Ce(m)/Ce(iv) couple related to a Ce(iv)-assisted process for SO2/NOx abatement

This paper presents the results of electrochemical investigations of the Ce(lii)/Ce(iv) couple, for use in a SO₂/NO_x abatement process. A voltammetric study was conducted at a platinum rotating disc electrode for the conditions corresponding to the gas scrubbing processes. The charge transfer coefficients were weakly affected by increasing the concentration of sulfuric acid up to 5 m. Conversely, the diffusion coefficients and the rate constants were decreasing functions of the concentration of sulfuric acid. The electrochemical regeneration of Ce(iv) was also studied at a platinized titanium surface and the oxidation appeared to be linked to other oxidative processes such as O₂ formation. Batch experiments, carried out in a filter press cell, showed good faradaic yields even in the potential domain corresponding to significant background current attributable to the supporting electrolyte.