In Situ X‑ray Diffraction Studies on the De/rehydrogenation Processes of the K2[Zn(NH2)4]‑8LiH System
journal contribution
posted on 2017-01-17, 13:34 authored by Hujun Cao, Claudio Pistidda, Theresia M. M. Richter, Antonio Santoru, Chiara Milanese, Sebastiano Garroni, Jozef Bednarcik, Anna-Lisa Chaudhary, Gökhan Gizer, Hanns-Peter Liermann, Rainer Niewa, Chen Ping, Thomas Klassen, Martin DornheimIn 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.
