Exploring gaseous hydrogen uptake in pipeline steel using a combined experimental-theoretical approach: the importance of surface state

In the context of combatting climate change, hydrogen can play a key role as an energy vector in diminishing CO2 emissions if produced from renewable sources. For its storage, one viable option is to store hydrogen under high-pressure, high-strength vessels in its molecular (H2) form. However, storing hydrogen gas in steel pressure vessels/pipelines runs the risk of hydrogen embrittlement and dangerous failures. The physical chemistry of hydrogen entry processes – the first steps prior to letting “externally produced” atomic hydrogen occupy precarious positions in the matrix– are far-ranging. Low carbon pipeline steels are covered with iron oxides and the role of iron oxides against hydrogen entry is dismissed as protective. Yet, this judgement remains questionable in the light of assuring integrity of these high-pressure hydrogen-filled gas pipelines for decades to come. It is therefore essential to explore in more detail the mechanism how hydrogen interacts, adsorbs on the iron oxide interface and diffuses into the surface sublayer.  
In the proposed PhD study, the interaction of hydrogen and iron oxide is studied both experimentally and by molecular simulations. Surface analysis techniques like LEED/STM/XPS will be performed on a bare iron oxide grown on an iron crystal as well after hydrogen dosages, while ToF-SIMS to analyse the penetrated hydrogen. Additionally, the impact of contaminants like H2S on the hydrogen uptake will be investigated. 
A mechanistic molecular modelling study based on density functional theory will closely accompany the experimental volet, which describes both thermodynamical and kinetically the processes of hydrogen adsorption and absorption into the subsurface.
This PhD position is available at IFP Energies nouvelles and in close collaboration with the PCS group of the Institute de Recherche de Chimie Paris, ENSCP, CNRS, PSL Research University.