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Improved Hydrogen‐Storage Thermodynamics and Kinetics for an RbF‐Doped Mg(NH 2 ) 2 –2 LiH System
Author(s) -
Li Chao,
Liu Yongfeng,
Gu Yingjie,
Gao Mingxia,
Pan Hongge
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201300323
Subject(s) - dehydrogenation , hydrogen storage , hydrogen , enthalpy , kinetics , ball mill , chemistry , activation energy , chemical kinetics , thermodynamics , doping , analytical chemistry (journal) , materials science , inorganic chemistry , catalysis , chromatography , organic chemistry , metallurgy , physics , optoelectronics , quantum mechanics
The introduction of RbF into the Mg(NH 2 ) 2 –2 LiH system significantly decreased its (de‐)hydrogenation temperatures and enhanced its hydrogen‐storage kinetics. The Mg(NH 2 ) 2 –2 LiH–0.08 RbF composite exhibits the optimal hydrogen‐storage properties as it could reversibly store approximately 4.76 wt % hydrogen through a two‐stage reaction with the onset temperatures of 80 °C for dehydrogenation and 55 °C for hydrogenation . At 130 °C, approximately 70 % of hydrogen was rapidly released from the 0.08 RbF‐doped sample within 180 min, and the fully dehydrogenated sample could absorb approximately 4.8 wt % of hydrogen at 120 °C. Structural analyses revealed that RbF reacted readily with LiH to convert to RbH and LiF owing to the favorable thermodynamics during ball‐milling. The newly generated RbH participated in the following dehydrogenation reaction, consequently resulting in a decrease in the reaction enthalpy change and activation energy.