Solid polymer electrolysis system for tritium enrichment using gold catalyst

Abstract: Solid polymer electrolyte (SPE) water electrolysis can effectively concentrate tritium using the tritium-to hydrogen (T/H) separation factor, serving as a crucial reference standard. The catalyst and optimization of the working conditions can significantly enhance the kinetic isotope effect (KIE), thereby improving the separation factor. In this study, various commercial cathode catalysts and operating conditions were tested. The use of Au/C in the cathode resulted in a separation factor that was twice that of Pt/C. The working conditions included the electrolysis temperature and electrolytic current. For this purpose, a novel tritium enrichment system (TES) was developed using Au/C as the cathode under optimized working conditions of 2.5°C and 25A. It achieved a high T/H separation factor of 20.44 via the Direct Method (DM) and a typical tritium recovery factor of 75.7%. Our research shows that the Enrichment Method (EM) is more convenient, but more susceptible to the influence of dead volume, with an error rate of 43%. Additionally, the recovery factor of the system in the replicated experiments varied minimally (0.4–0.6%), demonstrating high repeatability.