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Potassium Silanide (KSiH 3 ): A Reversible Hydrogen Storage Material
Author(s) -
Chotard JeanNoël,
Tang Wan Si,
Raybaud Pascal,
Janot Raphaël
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201101865
Subject(s) - hydrogen storage , dehydrogenation , hydrogen , enthalpy , density functional theory , hydride , thermodynamics , neutron diffraction , ternary operation , materials science , chemistry , crystallography , computational chemistry , crystal structure , physics , organic chemistry , computer science , programming language , catalysis
KSi silicide can absorb hydrogen to directly form the ternary KSiH 3 hydride. The full structure of α‐KSiD 3 , which has been solved by using neutron powder diffraction (NPD), shows an unusually short SiD lengths of 1.47 Å. Through a combination of density functional theory (DFT) calculations and experimental methods, the thermodynamic and structural properties of the KSi/α‐KSiH 3 system are determined. This system is able to store 4.3 wt % of hydrogen reversibly within a good P – T window; a 0.1 M Pa hydrogen equilibrium pressure can be obtained at around 414 K. The DFT calculations and the measurements of hydrogen equilibrium pressures at different temperatures give similar values for the dehydrogenation enthalpy (≈23 kJ mol −1 H 2 ) and entropy (≈54 J K −1 mol −1 H 2 ). Owing to its relatively high hydrogen storage capacity and its good thermodynamic values, this KSi/α‐KSiH 3 system is a promising candidate for reversible hydrogen storage.