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Syntheses of alkali-metal carbazolides for hydrogen storage
- Source :
- International Journal of Hydrogen Energy. 46:11051-11058
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- Metalorganic hydrides are a new class of hydrogen storage materials. Replacing the H of N–H or O–H functional groups using metal hydrides have been recently reported, which substantially improved the dehydrogenation properties of heteroaromatic organic hydrides by lowering their enthalpies of dehydrogenation (ΔHd), enabling dehydrogenation at much lower temperatures. Among the reported metalorganic hydrides, lithium carbazolide and sodium carbazolide appear to be the most attractive hydrogen storage/delivery material owing to its high hydrogen capacity (>6.0 wt%) and ideal ΔHd. Nevertheless, the interaction of carbazole and corresponding metal hydride to form metallo-carbazolide is a multistep process involving intensive ball milling and high temperature treatment, where the interaction was not investigated in detail. In this paper, both alkali metal hydrides and amides were employed to react with carbazole to synthesize corresponding carbazolides, aiming to broaden and optimize the synthetic method and understand the reaction mechanism. Our experimental results showed that around one equivalent of H2 or NH3 could be released from the reactions of carbazole and corresponding hydrides or amides, respectively. Instrumental spectroscopic analyses proved that metallo-carbazolides were successfully synthesized from all precursors. It is found that the alkali metal amides (i.e., LiNH2 and NaNH2) with stronger Lewis basicities as metal precursors could synthesize the metallo-carbazolides under milder conditions. Furthermore, quasi in situ nuclear magnetic resonance results revealed that alkali metal could replace H (H–N) gradually, donating more electrons to carbazole ring. Additionally, the solubilized alkali cation may unselectively interact with π-electron of aromatic systems of both carbazole molecules and carbazolide anions via electrostatic cation-π interactions.
- Subjects :
- Hydrogen
Renewable Energy, Sustainability and the Environment
Chemistry
Carbazole
Hydride
Inorganic chemistry
Energy Engineering and Power Technology
chemistry.chemical_element
02 engineering and technology
010402 general chemistry
021001 nanoscience & nanotechnology
Condensed Matter Physics
Alkali metal
01 natural sciences
0104 chemical sciences
Metal
Hydrogen storage
chemistry.chemical_compound
Fuel Technology
visual_art
visual_art.visual_art_medium
Dehydrogenation
Lithium
0210 nano-technology
Subjects
Details
- ISSN :
- 03603199
- Volume :
- 46
- Database :
- OpenAIRE
- Journal :
- International Journal of Hydrogen Energy
- Accession number :
- edsair.doi...........d1cbf1cbdaff2e0d7f69b5adb85fb2a5