Electrochemical Ce(III)/Ce(IV) Redox Behavior and Ce Oxide Nanostructure Recovery over Thio-Terpyridine-Functionalized Au/Carbon Paper Electrodes

Understanding the electrochemical behaviors of Ce(III)/Ce(IV) ions is essential for better treatment, separation, and recycling of lanthanide (Ln) and actinide (An) elements. Herein, electrochemical redox behavior and interconversion of Ce(III)/Ce(IV) ions and their recoveries were demonstrated over newly developed thio-terpyridine-functionalized Au-modified carbon paper electrodes in acidic and neutral electrolytes. Cyclic voltammetry and amperometry were performed for the electrodes with and without thio-terpyridine functionalization. Ce oxide nanostructure recovery was successfully conducted by amperometry, and the electrodeposited nanostructured Ce materials were fully characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction crystallography, and X-ray photoelectron spectroscopy. Geometry optimization and the electronic energy state calculations were conducted by density functional theory at the B3LYP/GENECP level for the complexes of Ce(III) and Ce(IV) ions with the thio-terpyridine in an aqueous state. The present unique results provide valuable information on understanding redox behaviors of Ln and An ions for their recycling and treatment processes.

Automated summary

Understanding the electrochemical behaviors of Ce(III)/Ce(IV) ions is crucial for the treatment, separation, and recycling of lanthanide and actinide elements. This study successfully demonstrated the electrochemical redox behavior, interconversion, and recovery of Ce(III)/Ce(IV) ions using thio-terpyridine-functionalized Au-modified carbon paper electrodes, providing valuable insights for the recycling and treatment processes of Ln and An ions. The results were fully characterized using various microscopy and spectroscopy techniques, along with density functional theory calculations for the Ce(III) and Ce(IV) ion complexes with thio-terpyridine.