Electrochemistry of CeCl₃ in molten LiCl-KCl eutectic

Abstract

The electrochemical properties of CeCl₃, dissolved in LiCl-KCl eutectic melt, were investigated by electrochemical techniques, such as cyclic voltammetry and square wave voltammetry on Mo electrode. It was shown that Ce(III) is reduced to Ce(0) based on a three-step mechanism. In a temperature range of 833–923 K, the diffusion coefficient of Ce(III) is lgD _Ce(III)= −2.49–1704/T determined by means of the Berzins-Delahay equation with two different expressions under reversible and irreversible conditions. The apparent standard potential of a Ce(III)/Ce(0) red-ox system is $E_{Ce^{3 + } /Ce^0 }^{0*} $=3.551+0.0006132T(K) vs. Cl₂/Cl⁻. Some thermochemical properties of CeCl₃ solutions were also derived from the electrochemical measurements, such as the enthalpy, entropy, Gibbs free energies and the activity coefficients of Ce(III). The Gibbs free energy of a dilute solution of CeCl₃ in this system was determined to be $\Delta G_{CeCl_3 }^{0*} $/(kJ·mol⁻¹)= −1027.9+0.178T(K) And the activity coefficients, $\gamma _{CeCl_3 } $, range between (7.78–9.14)×10⁻³. Furthermore, the standard rate constant of kinetic reaction was calculated to be (4.94–9.72)×10⁻³ cm²/s and the reaction was regarded as a quasi-reversible reaction under the present experimental conditions at 833 K.

Keywords

LiCl-KCl eutectic melt / CeCl₃ / Standard rate constant / Standard apparent potential / Activity coefficient

References

[1] Gibilaro M, Massot L, Chamelot P, Taxil P. J. Nucl. Mater., 2008, 382: 39.

[2] Gibilaro M, Massot L, Chamelot P, Cassayre L, Taxil P. Electrochim. Acta, 2009, 54: 5300.

[3] Yan Y D, Xu Y L, Zhang M L, Xue Y, Han W, Huang Y, Chen Q, Zhang Z J. J. Nucl. Mater., 2013, 433: 152.

[4] Sun Y, Zhang M L, Han W, Li M, Yang Y S. Chem. Res. Chinese Universities, 2013, 29(2): 324.

[5] Iizuka M. J. Electrochem. Soc., 1998, 145: 84.

[6] Chen L J, Zhang M L, Han W, Yan Y D, Cao P. Chem. J. Chinese Universities, 2012, 33(2): 327.

[7] Castrillejo Y, Hernández P, Rodriguez J A, Vega M, Barrado E. Electrochim. Acta, 2012, 71: 166.

[8] Tang H, Yan Y D, Zhang M L, Xue Y, Zhang Z J, Du W C, He H. Acta Phys. Chim. Sin., 2013, 29: 1698.

[9] Marsden K C, Pesic B. J. Electrochem. Soc., 2011, 158: 111.

[10] Betancourtt R, Nattland D. Chem. Phys., 2005, 7: 173.

[11] Castrillejo Y, Bermejo M, Millan R, Martínez A, Barrado E, Caravaca C, Arocas P. Progress in Molten Salt Chemistry, 2000, New York: Elsevier.

[12] Castrillejo Y, Bermejo M R, Pardo R, Martínez A M. J. Electroanal. Chem., 2002, 552: 124.

[13] Castrillejo Y, Bermejo M R, Barrado E, Martínez A M, Díaz Arocas P. J. Electroanal. Chem., 2003, 545: 141.

[14] Fusselman S P, Roy J J, Grimmett D L, Grantham L F, Krueger C L, Nabelek C R, Storvick T S, Inoue T, Hijikata T, Kinoshita K, Sakamura Y, Uozumi K, Kawai T, Takahashi N. J. Electrochem. Soc., 1999, 146: 2573.

[15] Lantelme F, Cartailler T, Berghoute Y, Hamdani M. J. Electrochem. Soc., 2001, 148: C604.

[16] Kim T, Ahn D H, Paek S W, Jung Y. J. Electrochem. Sci., 2013, 8: 9180.

[17] Zhang M, Han W, Zhang M L, Zhu F Y, Xue Y, Zhang Z J. J. Rare Earths, 2013, 31: 609.

[18] Han W, Zhang Y, Ye K, Yan Y, Zhang M. Mater. Trans. B, 2010, 41: 1123.

[19] Matsuda H, Ayabe Y. Z., Fur Elektrochem., 1955, 59: 494.

[20] Ogura T, Sasaki K, Takao K, Arai T, Ikeda Y. Sci. China Chem., 2012, 55: 1699.

[21] Pletcher D, Greef R, Peat R, Peter L M, Robinson J. Instrumental Methods in Electrochemistry, 2001, London: Horwood Publish Ltd..

[22] Bard A J, Faulkner L R. Electrochemical Methods: Fundamentals and Applications, 2001, New York: John Wiley & Sons 201.

[23] Osteryoung J, Osteryoung R A. Anal. Chem., 1985, 57: 101.

[24] Ramaley L, Krasue M S. Anal. Chem., 1969, 41: 1362.

[25] Berzins T, Delahay P. J. Am. Chem. Soc., 1953, 75: 555.

[26] Delahay P. New Instrumental Methods in Electrochemistry: Theory, Instrumentation, and Application to Analytical and Physical Chemistry, 1954, New York: Interscience.

[27] Masset P, Bottomley D, Konings R, Malmbeck R, Rodrigues A, Serp J, Glatz J P. J. Electrochem. Soc., 2005, 152: A1109.

[28] Yang L, Hudson R G. J. Electrochem. Soc., 1959, 106: 986.

[29] Pankratz L B. Thermodynamic Properties of Halides, 1984, Bulletin: Bureau of Mines 674.

[30] Nicholson R S. Anal. Chem., 1965, 37: 1351.

[31] Kuznetsov S A, Kuznetsova S V, Stangrit P T. Soviet Electrochem., 1990, 26: 55.