Lucie BADOURIC
defended her PhD thesis on 18 December 2024
“Atomic Layer Deposition for novel hydrogen separation membranes”
Front of the jury composed of:
– M. Mikhael BECHELANY, Directeur de Recherche CNRS, – Université de Montpellier – Directeur de thèse
– Mme. Anne JULBE, Directrice de Recherche CNRS, Université de Montpellier – Co-directrice de thèse
– M. Martin DROBEK, Chargé de Recherche CNRS, Université de Montpellier – Co-encadrant
– Mme. Catherine MARICHY, Chargée de Recherche CNRS, Université Claude Bernard Lyon 1 – Rapportrice
– M. Romain COUSTEL, Maître de Conférences, Université de Lorraine – Rapporteur
– M. Lionel SANTINACCI, Directeur de Recherche CNRS, Université Aix-Marseille – Examinateur
Abstract:
Hydrogen has emerged in recent years as a promising energy carrier to address the imminent depletion of fossil fuels and the intermittency of renewable energy sources. Hydrogen gas is typically produced through processes that generate gaseous impurities such as methane, carbon dioxide, carbon monoxide, and sulfur compounds. Therefore, efficient and sustainable hydrogen filtration methods are needed to enable its transportation, storage, and use. This PhD work focuses on the preparation of hydrogen-selective membranes synthesized by atomic/molecular layer deposition (ALD/MLD). All the membranes presented are supported by asymmetric porous alumina tubular substrates, ensuring mechanical strength and potential industrial applications.
A first membrane, based on palladium deposited by ALD was synthesized with the help of a prior alumina layer also deposited by ALD. This improved palladium nucleation and therefore enhanced hydrogen separation. The composition and morphology of the membrane were studied using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and atomic force microscopy (AFM). The stability of the membrane in the presence of a toxic contaminant such as carbon monoxide (CO) was monitored through gas mixture separation measurements. Additionally, this membrane stands out for its resistance to temperature cycling, a common issue with dense palladium membranes. The developed membrane maintained its separation performance after a full temperature cycle, increasing its application potential. In parallel, a second membrane based on an organic-inorganic hybrid alucone layer was synthesized by MLD. After optimizing the thermal treatment conditions, a microporous network mainly composed of alumina was formed in/on the mesoporous support layer. The formation process of this microporous layer was studied using thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and XPS. Promising hydrogen separation performance were observed during gas separation testing.
Finally, preliminary tests were conducted to protect the previously developed palladium membrane from CO poisoning. A nickel oxide (NiO) layer was deposited by ALD on the top of the palladium layer, and gas mixture separation measurements were performed. Additionally, tests were conducted to use the porous alumina-based membrane as a protective barrier against CO. Despite typical lower performance for the protected palladium membranes, good regeneration after CO exposure and a relatively high H2/CO separation factor in the case of porous alumina protection, represent interesting firsts results.
