Studies of ammonia decomposition for pressurized hydrogen production in reactors based on proton-conducting ceramic membranes

Background :

Hydrogen technologies are set to play a key role in the energy transition. This transition requires rapid development of water electrolysis to produce low-carbon H₂ for cross-sector industries such as steel and chemicals, e-fuel production (e-kerosene, e-methanol, etc.) and to support H₂ grid supply. Unfortunately, their deployment remains slow and insufficient. One of the challenges slowing down this deployment is the difficulty in storing and transporting H₂. In this project, we aim to use ammonia as a practical vector for transporting hydrogen. Indeed, there is already a global infrastructure for transporting and storing NH₃, as the molecule is used to synthesize fertilizers for agriculture. The overall objective of this project is to convert transported ammonia into hydrogen using a unique proton ceramic reactor integrating the steps of NH₃ decomposition and H₂ purification/compression. In this context, this PhD thesis project is particularly focused on the study of the decomposition reaction of NH₃ into H₂ and N₂, and the electrocatalytic mechanisms involved in this decomposition. With this knowledge, the student will then be able to propose new catalysts for their integration into the electrochemical reactor.

Research environment and resources:

The project will be done at the Institute of Materials of Nantes Jean Rouxel (IMN) in the Electrochemical Energy Storage and Transformations Team (ST2E). The ST2E team has extensive experience in the field of ceramic materials for solid oxide battery and electrolyzer applications operating at high temperatures (SOFC, PCFC). The electrocatalytic properties of the materials considered will be measured using a new technique set up at the IMN combining chemical (mass spectrometry) and electrical (4-point conductivity) measurements. This thesis is part of a Franco-German project in collaboration with the universities of Poitiers, Belfort, and Montpellier in France, and Karlsruhe, EIFER and the DLR center in Stuttgart in Germany. Visits to partner laboratories and regular meetings are planned during the thesis.

Candidate profile :

The ideal candidate must have a strong scientific interest in fundamental studies and a desire to develop expertise in solid state chemistry and electrocatalysis. Graduate from a master degree program or equivalent, the candidate should have trainings in ceramic materials synthesis (solid state reaction, Pechini, soft chemistry), characterizations (chemical analysis, X-ray diffraction, spectroscopy and microscopy), and electrochemical characterizations (electrical conductivity measurements, impedance spectroscopy). He/She will take part in research activities of the team and will have the opportunity to present their work in national and international conferences