In Situ X-ray Diffraction Studies on the De/rehydrogenation Processes of the K2[Zn(NH2)4]-8LiH System

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• 作者：Hujun CaoClaudio Pistidda ; Theresia M. M. Richter ; Antonio Santoru ; Chiara MilaneseSebastiano Garroni ; Jozef Bednarcik ; Anna-Lisa Chaudhary ; Gökhan Gizer ; Hanns-Peter Liermann ; Rainer Niewa ; Chen Ping ; Thomas Klassen ; Martin Dornheim
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 26, 2017
• 年：2017
• 卷：121
• 期：3
• 页码：1546-1551
• 全文大小：565K
• ISSN：1932-7455

文摘

In this work, the hydrogen absorption and desorption properties of the system K₂[Zn(NH₂)₄]-8LiH are investigated in detail via in situ synchrotron radiation powder X-ray diffraction (SR-PXD), Fourier transform infrared spectroscopy (FT-IR), and volumetric methods. Upon milling, K₂[Zn(NH₂)₄] and 8LiH react to form 4LiNH₂-4LiH-K₂ZnH₄, and then 4LiNH₂-4LiH-K₂ZnH₄ releases H₂ in multiple steps. The final products of the desorption reaction are KH, LiZn₁₃, and Li₂NH. During rehydrogenation, KH reacts with LiZn₁₃ under 50 bar of hydrogen producing K₃ZnH₅. This phase appears to enhance the hydrogenation process which after its formation at ca. 220 °C takes place in only 30 s. The system 4LiNH₂-4LiH-K₂ZnH₄ is shown to be reversible under the applied conditions of vacuum at 400 °C for desorption and 50 bar of H₂ at 300 °C for absorption.