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Improvement in Hydrogen Desorption from β‐ and γ‐MgH 2 upon Transition‐Metal Doping
Author(s) -
Hussain Tanveer,
Maark Tuhina Adit,
Chakraborty Sudip,
Ahuja Rajeev
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201500238
Subject(s) - density functional theory , transition metal , desorption , dopant , hydrogen , doping , hydrogen storage , materials science , chemistry , metal , adsorption , inorganic chemistry , computational chemistry , catalysis , metallurgy , biochemistry , optoelectronics , organic chemistry
A thorough study of the structural, electronic, and hydrogen‐desorption properties of β‐ and γ‐MgH 2 phases substituted by selected transition metals (TMs) is performed through first‐principles calculations based on density functional theory (DFT). The TMs considered herein include Sc, V, Fe, Co, Ni, Cu, Y, Zr, and Nb, which substitute for Mg at a doping concentration of 3.125 % in both the hydrides. This insertion of TMs causes a variation in the cell volumes of β‐ and γ‐MgH 2 . The majority of the TM dopants decrease the lattice constants, with Ni resulting in the largest reduction. From the formation‐energy calculations, it is predicted that except for Cu and Ni, the mixing of all the selected TM dopants with the MgH 2 phases is exothermic. The selected TMs also influence the stability of both β‐ and γ‐MgH 2 and cause destabilization by weakening the MgH bonds. Our results show that doping with certain TMs can facilitate desorption of hydrogen from β‐ and γ‐MgH 2 at much lower temperatures than from their pure forms. The hydrogen adsorption strengths are also studied by density‐of‐states analysis.