Pore with gate: modulating hydrogen storage in metal-organic framework materials via cation exchange
2011 (English)In: Faraday discussions (Online), ISSN 1364-5498, E-ISSN 1359-6640, Vol. 151, 19-36 p.Article in journal (Refereed) Published
A range of anionic metal-organic framework (MOF) materials has been prepared by combination of In(III) with tetracarboxylate isophthalate-based ligands. These materials incorporate organic cations, either H(2)ppz(2+) (ppz = piperazine) or Me(2)NH(2)(+), that are hydrogen bonded to the pore wall. These cations act as a gate controlling entry of N(2) and H(2) gas into and out of the porous host. Thus, hysteretic adsorption/desorption for N(2) and H(2) is observed in these systems, reflecting the role of the bulky hydrogen bonded organic cations in controlling the kinetic trapping of substrates. Post-synthetic cation exchange with Li(+) leads to removal of the organic cation and the formation of the corresponding Li(+) salts. Replacement of the organic cation with smaller Li(+) leads to an increase in internal surface area and pore volume of the framework material, and in some cases to an increase in the isosteric heat of adsorption of H(2) at zero coverage, as predicted by theoretical modelling. The structures, characterisation and analysis of these charged porous materials as storage portals for H(2) are discussed. Inelastic neutron scattering experiments confirm interaction of H(2) with the carboxylate groups of the isophthalate ligands bound to In(III) centres.
Place, publisher, year, edition, pages
2011. Vol. 151, 19-36 p.
IdentifiersURN: urn:nbn:se:su:diva-66879DOI: 10.1039/c1fd00006cISI: 000293517400003OAI: oai:DiVA.org:su-66879DiVA: diva2:468941
authorCount :82011-12-222011-12-212011-12-22Bibliographically approved