Hydrogen sensor for application in reusable launch vehicles

Abstract

We have been developing a novel hydrogen sensor using sintered ceria (CeO_2−σ) nanoparticles in a collaboration with the Japan Aerospace Exploration Agency for application in spacecraft. The sensor can rapidly detect hydrogen in vacuum or oxygen-free conditions. This property originates from the fact that ceria is an oxide ion–electron mixed conductor. In this paper, the adsorption state of gases on the ceria surface is discussed based on the relationship between the gas partial pressure and carrier concentration. In addition, the sensing mechanism is clarified by combining the results of the in-situ X-ray absorption fine structure analysis of the valence change of ceria before and after hydrogen adsorption.