TY - JOUR
T1 - Thermodynamical stabilities of metal-borohydrides
AU - Nakamori, Y.
AU - Li, H. W.
AU - Kikuchi, K.
AU - Aoki, M.
AU - Miwa, K.
AU - Towata, S.
AU - Orimo, S.
N1 - Funding Information:
The authors would like to thank T. Noritake and S. Hyodo for valuable discussion, and N. Warifune for her technical support. This study was partially supported by the New Energy and Industrial Technology Development Organization (NEDO), International Joint Research under the “Development for Safe Utilization and Infrastructure of hydrogen” Project (2005–2006), by the Ministry of Education, Science, Sports and Culture, “Grant-in-Aid for Encouragement of Young Scientists (B), #17760555” and for Scientific Research (A), #18206073”.
PY - 2007/10/31
Y1 - 2007/10/31
N2 - Metal-borohydrides M(BH4)n (M = Ca, Sc, Ti, V, Cr, Mn, Zn (fourth period in periodic table) and Al; n = 2-4) were synthesized by a mechanical milling process according to the following reaction: MCln + nLiBH4 → M(BH4)n + nLiCl. The thermal desorption properties of M(BH4)n were investigated by gas-chromatography and mass-spectroscopy combined with thermogravimetry. The results indicate that the hydrogen desorption temperature Td of M(BH4)n correlates with the Pauling electronegativity χP of M; that is, Td decreases with increasing values of χP. The components of desorbed gas for M = Ca, Sc, Ti, V and Cr (χP ≤ 1.5) are hydrogen only, while those for M = Mn, Zn and Al (χP ≥ 1.5) contain borane and hydrogen. Therefore, the appropriate χP in M(BH4)n for hydrogen storage is expected to be smaller than 1.5, and the resulting predicted relationship between the heat of formation of M(BH4)n and χP is a useful indicator for estimating the enthalpy change for the desorption reaction for M(BH4)n.
AB - Metal-borohydrides M(BH4)n (M = Ca, Sc, Ti, V, Cr, Mn, Zn (fourth period in periodic table) and Al; n = 2-4) were synthesized by a mechanical milling process according to the following reaction: MCln + nLiBH4 → M(BH4)n + nLiCl. The thermal desorption properties of M(BH4)n were investigated by gas-chromatography and mass-spectroscopy combined with thermogravimetry. The results indicate that the hydrogen desorption temperature Td of M(BH4)n correlates with the Pauling electronegativity χP of M; that is, Td decreases with increasing values of χP. The components of desorbed gas for M = Ca, Sc, Ti, V and Cr (χP ≤ 1.5) are hydrogen only, while those for M = Mn, Zn and Al (χP ≥ 1.5) contain borane and hydrogen. Therefore, the appropriate χP in M(BH4)n for hydrogen storage is expected to be smaller than 1.5, and the resulting predicted relationship between the heat of formation of M(BH4)n and χP is a useful indicator for estimating the enthalpy change for the desorption reaction for M(BH4)n.
UR - http://www.scopus.com/inward/record.url?scp=35148890903&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=35148890903&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2007.03.144
DO - 10.1016/j.jallcom.2007.03.144
M3 - Article
AN - SCOPUS:35148890903
SN - 0925-8388
VL - 446-447
SP - 296
EP - 300
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -