CYCLIC VOLTAMMETRY STUDY OF Ce(IV)/Ce(III) REDOX COUPLE AND Ce(IV)-F COMPLEX IN SULFURIC ACID MEDIUM

J. G. He, Y. Li, X. X. Xue, H. Q. Ru, H. Yang, School of Material and Metallurgy, Northeastern University, Shenyang, China; X. W. Huang, National Engineering Research Center for Rare Earth Materials, General Research Institute for Nonferrous Metals, and Grirem Advanced Materials Co., Ltd., Beijing, China. In this paper the electrochemical behaviors of Ce(IV)/Ce(III) redox couple and Ce(IV) F complex in sulfuric acid medium were studied by cyclic voltammetry using a platinum electrode. Both of the Ce(IV)/Ce(III) couple in Ce(IV) solution and Ce(IV) F complex is a quasi-reversible process, and gives a linear correlation between the peak potentials and square root of scan rates, showing that the kinetics of the overall process is diffusion controlled. The complexation of cerium(IV) and fluoride is favorable for the oxidation of Ce(III). The kinetic parameters such as diffusion coefficients, anodic transfer coefficients and rate constants were studied.