Electrochemiluminescence in the reduction of uranyl ions on platinum in sulfuric acid solutions

Electrochemiluminescence (ECL) accompanying the reduction of uranyl ions on a platinum cathode in sulfuric solutions in the presence of XeO₃ was observed and studied. At early stages of the electrolysis (at 0.34<φ<0.62 V), the chemiluminescence reaction U^V+XeO₃ contributes mainly to the luminescence intensity, whereas at φ<0.32 V, the contribution of the reaction U^IV+XeO₃ predominates. The transfer coefficient for the primary electrochemical stage, formation of U^V, was estimated: α=0.46−0.54. The high sensitivity of ECL to the state of the electrode surface is explained by the fact that the reduction of U^VI occurs on the most active sites only. the background chemiluminescence reactions, among which U^V+O₂ and U^V+H₂O₂ can be distinguished, were considered, and their contributions to ECL were determined. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1928–1934, October, 1999.