Small-pore hydridic frameworks store densely packed hydrogen

• Published in: Nature chemistry Vol. 16; no. 5; pp. 809 - 816
• Main Authors: Oh, Hyunchul, Tumanov, Nikolay, Ban, Voraksmy, Li, Xiao, Richter, Bo, Hudson, Matthew R, Brown, Craig M, Iles, Gail N, Wallacher, Dirk, Jorgensen, Scott W, Daemen, Luke, Balderas-Xicohténcatl, Rafael, Cheng, Yongqiang, Ramirez-Cuesta, Anibal J, Heere, Michael, Posada-Pérez, Sergio, Hautier, Geoffroy, Hirscher, Michael, Jensen, Torben R, Filinchuk, Yaroslav
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 01.05.2024; Nature Publishing Group UK
• Subjects: Adsorption; Borohydrides; First principles; Hydrogen; Inelastic scattering; Liquid hydrogen; Magnesium; Neutron diffraction; Neutron scattering; Neutrons; Nitrogen; Pores; Storage capacity; Storage conditions
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/s41557-024-01443-x

Nanoporous materials have attracted great attention for gas storage, but achieving high volumetric storage capacity remains a challenge. Here, by using neutron powder diffraction, volumetric gas adsorption, inelastic neutron scattering and first-principles calculations, we investigate a magnesium borohydride framework that has small pores and a partially negatively charged non-flat interior for hydrogen and nitrogen uptake. Hydrogen and nitrogen occupy distinctly different adsorption sites in the pores, with very different limiting capacities of 2.33 H and 0.66 N per Mg(BH ) . Molecular hydrogen is packed extremely densely, with about twice the density of liquid hydrogen (144 g H per litre of pore volume). We found a penta-dihydrogen cluster where H molecules in one position have rotational freedom, whereas H molecules in another position have a well-defined orientation and a directional interaction with the framework. This study reveals that densely packed hydrogen can be stabilized in small-pore materials at ambient pressures.