Fast electrodeposition of short-lived tellurium radioisotopes by flow electrolytic underpotential deposition on Au and Pt

Electrodeposition is an attractive strategy for the purification and separation of radionuclides. Applications include their production for uses related to cancer diagnostic and therapy, their analytical characterization, and fundamental studies of the chemical properties of radioelements, including superheavy elements. In many of the mentioned applications, short-lived radionuclides are present in ultra-trace quantities. As a result, their electrodeposition is largely influenced by underpotential deposition (UPD) and cannot be studied by conventional electrochemical means. The aim of this work was the design and implementation of a methodology which enables the study of the electrodeposition behavior of short-lived radionuclides at carrier-free conditions. These were obtained in the form of fission products from the neutron-induced fission of ²³⁵U and their transport <em>via</em> the gas-jet technique. A mixer-degasser unit was implemented for the direct online transfer of ≈50% radionuclide-loaded aerosol particles into the liquid phase. This enabled the interfacing of the SINQ gas-jet system with a flow-through electrolysis cell for the cathodic electrodeposition of short-lived ¹³⁴Te as proof-of-concept. Based on a comparison with results from cyclic voltammetry, UPD was shown to be the main mechanism responsible for the electrodeposition of ¹³⁴Te on Au and Pt. Furthermore, it could be demonstrated that UPD affords a fast separation of short-lived radionuclides in carrier-free conditions by fine-tuning the electrode material and chemical conditions. The developed approach enables the determination of electrochemical properties of short-lived radionuclides <em>via</em> their separation at carrier-free concentrations.