In:
Angewandte Chemie, Wiley, Vol. 133, No. 49 ( 2021-12), p. 26019-26028
Abstract:
The highly unfavorable thermodynamics of direct aluminum hydrogenation can be overcome by stabilizing alane within a nanoporous bipyridine‐functionalized covalent triazine framework (AlH 3 @CTF‐bipyridine). This material and the counterpart AlH 3 @CTF‐biphenyl rapidly desorb H 2 between 95 and 154 °C, with desorption complete at 250 °C. Sieverts measurements, 27 Al MAS NMR and 27 Al{ 1 H} REDOR experiments, and computational spectroscopy reveal that AlH 3 @CTF‐bipyridine dehydrogenation is reversible at 60 °C under 700 bar hydrogen, 〉 10 times lower pressure than that required to hydrogenate bulk aluminum. DFT calculations and EPR measurements support an unconventional mechanism whereby strong AlH 3 binding to bipyridine results in single‐electron transfer to form AlH 2 (AlH 3 ) n clusters. The resulting size‐dependent charge redistribution alters the dehydrogenation/rehydrogenation thermochemistry, suggesting a novel strategy to enable reversibility in high‐capacity metal hydrides.
Type of Medium:
Online Resource
ISSN:
0044-8249
,
1521-3757
DOI:
10.1002/ange.v133.49
DOI:
10.1002/ange.202107507
Language:
English
Publisher:
Wiley
Publication Date:
2021
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