Hydrogen sensor for application in reusable launch vehicles

Abstract

We have been developing a novel hydrogen sensor using sintered ceria (CeO₂-σ) nanoparticles in collaboration with JAXA for spacecraft applications. This sensor is able to rapidly detect hydrogen in either vacuum or oxygen-free condition. This property has originated from the fact that ceria is an oxide ion-electron mixed conductor. In this article, the adsorption state of gases on the ceria surface is discussed based on the relationship between the gas partial pressure and the carrier concentration. In addition, the sensing mechanism is clarified by combining the results of in-situ XAFS analysis of the valence change of ceria before and after hydrogen adsorption.