Syntheses of alkali-metal carbazolides for hydrogen storage
| Autor: | Teng He, Khai Chen Tan, Yong Shen Chua, Yang Yu, Dewen Zheng, Xi Zhang, Zhixin Ge, Fudong Zhang, Qijun Pei, Zijun Jing |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
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 |
| Zdroj: | International Journal of Hydrogen Energy. 46:11051-11058 |
| ISSN: | 0360-3199 |
| DOI: | 10.1016/j.ijhydene.2020.06.024 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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