https://doi.org/10.1051/epjconf/202328605001
The ortho-para transition, confinement and self-diffusion of H2 in three distinct carbide-derived carbons by quasi- and inelastic neutron scattering
1 Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
2 Department of Applied Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden
3 Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
4 Department of Geology, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
5 Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232, Villigen PSI, Switzerland
* Corresponding author: riinu.harmas@ut.ee
Published online: 9 October 2023
Microporous carbon materials are promising for hydrogen storage due to their structural variety, high specific surface area, large pore volume and relatively low cost. Carbide-derived carbons are highly valued as model materials because their porous structure is fine-tuned through the choice of the precursor carbide and the synthesis route. This study investigates H2 adsorption in three carbide derived carbons with well-defined pores and pore size distributions with quasi- and inelastic neutron scattering methods. Concerning previous studies, a wider neutron energy transfer window is investigated, and a detailed quantitative evaluation of the graphitic structure is presented. The graphitic structure of the carbon is shown to influence the speed of the ortho-to-para transition of H2. Namely, the ortho-para transition was the slowest in carbon derived from TiC, which also had the smallest average stacking size of graphene layers. The possibility to inhibit the ortho-para transition in cryo-adsorption devices is sought after to mitigate the evaporation of H2 during storage. In addition, the self-diffusion of H2 in different timescales is detected in carbon derived from Mo2C, demonstrating the usefulness of obtaining data in a wide energy window.
© The Authors, published by EDP Sciences, 2023
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
