Mechanism of hydrogenation reaction in the Li-Mg-N-H system

Haiyan Leng; Takayuki Ichikawa; Satoshi Hino; Tessui Nakagawa; Hironobu Fujii

doi:10.1021/jp0504571

Mechanism of hydrogenation reaction in the Li-Mg-N-H system

J Phys Chem B. 2005 Jun 2;109(21):10744-8. doi: 10.1021/jp0504571.

Authors

Haiyan Leng¹, Takayuki Ichikawa, Satoshi Hino, Tessui Nakagawa, Hironobu Fujii

Affiliation

¹ Materials Science Center, N-BARD, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan. hyleng@hiroshima-u.ac.jp

PMID: 16852305
DOI: 10.1021/jp0504571

Abstract

The Li-Mg-N-H system composed of 3 Mg(NH2)2 and 8 LiH reversibly desorbs/absorbs approximately 7 wt % of H2 at 120-200 degrees C and transforms into 4 Li2NH and Mg3N2 after dehydrogenation. In this work, the mechanism of the hydrogenation reaction from 4 Li2NH and Mg3N2 to 8 LiH and 3 Mg(NH2)2 was investigated in detail. Experimental results indicate that 4 Li2NH is first hydrogenated into 4 LiH and 4 LiNH2. At the next step, 4 LiNH2 decomposes into 2 Li2NH and 2 NH3, and the emitted 2 NH3 reacts with (1/2) Mg3N2 and produces the (3/2) Mg(NH2)2 phase, while the produced 2 Li2NH is hydrogenated into 2 LiH and 2 LiNH2 again. Such successive steps continue until all 4 Li2NH and Mg3N2 completely transform into 8 LiH and 3 Mg(NH2)2 by hydrogenation.