Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.731849
Title: Hydrogen storage properties of nitrogen- and halogen- containing materials
Author: Du Plessis, Rachel Frances
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2017
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Abstract:
The Li−Mg−N−H system represents a promising system for a solid-state hydrogen store. Kinetic and thermodynamic improvements are required to bring the properties of this system to a suitable position. The effect of preparation conditions and the addition of dopant materials into this system were investigated by a variety of experimental techniques. The preparation method of the sample was found to be very important. The choice of initial preparation and desorption conditions can be used to control the phase of Li₂Mg(NH)₂ formed. Pressurised milling conditions (under 100 bar H₂) appeared to be successful in reducing gas release during milling, but changed the reaction pathway. The addition of 0.1 mole fraction of either calcium halide dopant, CaCl₂ or CaBr₂ lowered the peak hydrogen desorption temperature from this system. The activation energies of all the doped samples were reduced relative to the undoped samples prepared in the same manner. The reactions between MgH₂ and NH₄)Cl at various temperatures and stoichiometry’s were also investigated using several techniques. Solid-state reactions between these two reagents have not been carried out before. An unknown set of peaks was observed by powder XRD and a new phase, Mg(NH₄)₂Cl₄ was identified which was found to be iso-structural with Mg(NH₄)₂F₄.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.731849  DOI: Not available
Keywords: QD Chemistry
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