SSL Seminar Series 2004 No.5
Combined talks (two speakers)
Date: September 27 (Monday), 2004
Time: 4:00-5:00pm
Venue: Physics Resource Room (Blk S13 # 02-16)
Speaker I:Dr. Xiong Zhitao
Title: Hydrogen storage over alkali metal-N-H system
Abstract:
The demand for high efficient solid-state hydrogen storage materials
for the coming hydrogen economy encourages tremendous efforts in
the development of novel systems such as complex chemical hydrides
and carbonaceous materials. Lithium nitride, newcomers to the sorbent
system, exhibits strong affinity towards hydrogen molecules. 11.5wt%
of hydrogen can be absorbed via a two-step reaction with lithium
amide (LiNH2) and Lithium hydride (LiH) generated as final products.
Surprisingly, mixture of above two materials can desorb hydrogen
upon heating to 170oC. Hydrogen can not come from LiH for it’s
so stable and its decomposition occurs above 550oC. For LiNH2, it
will decompose to Li2NH and NH3 at 360oC. Thus, certain interaction
between LiNH2 and LiH should exist and be responsible for hydrogen
release at lower temperature. Enlightened from this point we had
some other systems compose of alkali metal amide and hydride tested
and we found that it’s a common rule and this rule can be
guidance for synthesis of hydrogen storage materials.
Speaker II: Dr.Hu Jianjiang
Title: Physicochemical Properties of metal amides and imides
Abstract:
In the search for efficient hydrogen storage materials, great attentions
have been caught by lithium nitride with its remarkable capacity
of H2 storage performance. Mechanism studies show that the lithium
amide and imide are the intermediates in the hydrogen absorption
/ desorption process. Like the approaches used in the metal H2 storage
materials, binary, ternary or multiparty nitrides have been reportedly
synthesized, which unprecedentedly enlarges and complexes the compound
categories of nitrides, imides and amides. Fundamental understandings
of these compounds, both in physicochemical properties and chemical
structures, will enable the elucidation of the interaction processes
between these kinds of materials and hydrogen. Using Differential
Scanning Calorimetry (DSC) and Diffuse Reflectance Infrared Fourier
Transform Spectroscopy (DRIFT), some thermodynamic and kinetic properties
and structural properties have been investigated.
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