TY - JOUR
T1 - EXAFS investigation of the destabilization of the Mg-Ni-Ti(H) system
AU - Zheng, Q.
AU - Pivak, Y.
AU - Mooij, L.P.A.
AU - van der Eerden, A.M.J.
AU - Schreuders, H.
AU - de Jongh, P.E.
AU - Bitter, J.H.
AU - Dam, B.
PY - 2012
Y1 - 2012
N2 - Ti doping destabilizes the Mg2NiH4 system, reducing the hydrogenation enthalpy from e
64 kJ/(mol H2) to around e 40 kJ/(mol H2). However, the equilibrium pressure is hardly
affected, as also the entropy of reaction changes. To understand this thermodynamic
behavior it is essential to understand the structure of the phases present in the Ti-doped
Mg2Ni system in metallic and hydrogenated state. We used Extended X-ray Absorption Fine
Structure (EXAFS) to investigate the local coordination of Ni and Ti atoms in MgeNieTi thin
films both in the as-prepared as well as in the hydrogenated state. In the as-prepared state
two phases, Mg2Ni and TiNi or TiNi3, are formed, which transform in a single Ti-doped
Mg2NiH4 phase in the hydrogenated state. These results are consistent with previous
DFT calculations for this system.
AB - Ti doping destabilizes the Mg2NiH4 system, reducing the hydrogenation enthalpy from e
64 kJ/(mol H2) to around e 40 kJ/(mol H2). However, the equilibrium pressure is hardly
affected, as also the entropy of reaction changes. To understand this thermodynamic
behavior it is essential to understand the structure of the phases present in the Ti-doped
Mg2Ni system in metallic and hydrogenated state. We used Extended X-ray Absorption Fine
Structure (EXAFS) to investigate the local coordination of Ni and Ti atoms in MgeNieTi thin
films both in the as-prepared as well as in the hydrogenated state. In the as-prepared state
two phases, Mg2Ni and TiNi or TiNi3, are formed, which transform in a single Ti-doped
Mg2NiH4 phase in the hydrogenated state. These results are consistent with previous
DFT calculations for this system.
U2 - 10.1016/j.ijhydene.2011.11.107
DO - 10.1016/j.ijhydene.2011.11.107
M3 - Article
SN - 0360-3199
VL - 37
SP - 4161
EP - 4169
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
IS - 5
ER -