“Green” hydrogen purification by metallic catalysts

To meet environmental commitments, France must regularly limit its greenhouse gas emissions to achieve carbon neutrality by 2050. For this purpose, the implementation of the hydrogen chain should allow to make a major contribution to the decarbonation of our heavy transport and industries. Among alternative solutions, the massive production of renewable (or low-carbon) hydrogen, based on the water electrolysis process gives high hopes.  
From a technical point of view, hydrogen produced by electrolysis is contaminated by small amounts of oxygen, which must be eliminated to meet the stringent hydrogen standards imposed by its storage and its use in fuel cells. Thus, its purification is achieved by a so called 'deoxo' process, using a platinum or palladium-based catalyst supported on alumina and converting residual oxygen in water (easier to separate). Although this reaction is rather easy, the stability of the catalytic systems is neither really controlled nor understood. This is therefore an important issue at the level of scientific research.
This PhD project aims thus to better understand the origin of the limit linked to the deactivation of the active phase, by probing various catalysts synthesized by different experimental ways. After a bibliographical survey of the experimental and theoretical literature, the PhD student will be trained to operate the existing catalytic test (as well as its analytical system) in order to characterize properly the ‘deoxo’ reaction. The experimental study aims to study and compare the performance (activity and stability) of various catalysts according to operating conditions (T, H2/O2/H2O pressures). Then, by considering the theoretical works published in the literature, and by undertaking his/her own density functional theory atomistic calculations, the PhD student will seek to understand the reaction mechanisms involved at the metallic surface and the origins of the active phase deactivation in reaction conditions. Various calculated (thermodynamic and kinetic) descriptors of the surface reactions will be explored as a function of the chemical potential of the medium in order to identify the physico-chemical phenomena driving the deactivation. Thanks to this combined experimental and theoretical approach, the ultimate objective would be to propose interesting catalytic systems for future industrial developments.

Keywords: hydrogen, purification, catalysis by metals, synthesis, computational chemistry

Academic supervisor    Dr. LOFFREDA David, Laboratoire de Chimie, ENS de Lyon http://www.ens-lyon.fr/CHIMIE/laboratory/directory/loffreda-david
Doctoral School    ED 206 (Ecole Doctorale de chimie de Lyon), https://www.edchimie-lyon.fr/
IFPEN supervisor    HUGON Antoine, PhD, antoine.hugon@ifpen.fr IFPEN co-supervisors    NARDIN Thibault, PhD RAYBAUD Pascal, PhD;  www.ifpenergiesnouvelles.fr/page/pascal-raybaud 
PhD location    IFP Energies nouvelles, Solaize, Fr & Laboratoire de Chimie, ENS de Lyon
Duration and start date    3 years, starting in fourth quarter 2023
Employer    IFPEN, Solaize, France
Academic requirements    University Master degree (or graduate engineer diploma) in relevant disciplines: chemistry, physico-chemistry, catalysis 
Language requirements    Fluency in French or English, willingness to learn French
Other requirements    Knowledge or strong motivation in computational chemistry applied to materials wished.