Redox behaviour of cerium (III) in LiF-CaF_2 eutectic melt

摘要

Electrochemical redox behaviour of Ce (III) ion in LiF-CaF_2 eutectic was studied at 1093 K using tungsten (inert) and nickel (reactive) as working electrodes and platinum as quasi-reference electrode by various electrochemical transient techniques viz. cyclic voltammetry (CV), square-wave voltammetry (SQWV) and chronopotentiometry (CP). It was deduced that reduction of Ce (III) to Ce metal occurs by a single step, three-electron transfer. Diffusion coefficient (D_(Ce(III))) of Ce (III) ion was determined from CV, semi-integral analysis and CP and the values obtained were 2.2 × 10~(-5), 5.4 × 10~(-5) and 3.0 × 10~(-5) cm~2 s~(-1), respectively. Electrochemical studies in the presence of Ni electrode showed the formation of the inter-metallic compounds CeNi_5 and Ce_2Ni_7, which were characterized by powder X-ray diffraction and SEM-EDAX analysis.