Solid-state electrochemical sensor for hydrogen isotopes. Part I: Modulating isotopic detection through surface engineering with graphene

Hydrogen and its isotopes are presented as an interesting alternative to fossil fuels because it is intended to use these species in the field of nuclear fusion, and in fields such as fuel cell technology, among others. To this end, the availability of sensors that can measure these isotopes in-situ and online is a key point for the correct development of these technologies. Electrochemical sensors based on solid-state electrolytes have been proved to be able to operate at elevated temperatures, with great physical and chemical stabilities. In this work, electrochemical sensors were constructed and tested using BaCe0.6Zr0.3Y0.1O3-α electrolytes. To achieve different isotopic responses, a graphene layer was transferred onto the surface of the working electrode. The sensors (with and without graphene) were used in a potentiometric and amperometric configuration at 500 °C. Analyte concentrations in the working electrode ranged from 0.12 to 1 mbar of H2 or D2 in Ar. The presence of graphene produced different sensor responses depending on the isotope. In addition, differences in response and recovery times were also observed, being both higher for the sensors with graphene.