Synthesis and decomposition mechanisms of Mg2FeH6 studied by in-situ synchrotron X-ray diffraction and high-pressure DSC

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Synthesis and decomposition mechanisms of Mg2FeH6 studied by in-situ synchrotron X-ray diffraction and high-pressure DSC. / Polanski, M.; Nielsen, T. K.; Cerenius, Yngve; Bystrzycki, J.; Jensen, T. R.

In: International Journal of Hydrogen Energy, Vol. 35, No. 8, 2010, p. 3578-3582.

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Polanski, M. ; Nielsen, T. K. ; Cerenius, Yngve ; Bystrzycki, J. ; Jensen, T. R. / Synthesis and decomposition mechanisms of Mg2FeH6 studied by in-situ synchrotron X-ray diffraction and high-pressure DSC. In: International Journal of Hydrogen Energy. 2010 ; Vol. 35, No. 8. pp. 3578-3582.

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TY - JOUR

T1 - Synthesis and decomposition mechanisms of Mg2FeH6 studied by in-situ synchrotron X-ray diffraction and high-pressure DSC

AU - Polanski, M.

AU - Nielsen, T. K.

AU - Cerenius, Yngve

AU - Bystrzycki, J.

AU - Jensen, T. R.

PY - 2010

Y1 - 2010

N2 - Synthesis and decomposition mechanisms of ternary Mg2FeH6 were investigated using in-situ synchrotron radiation powder X-ray diffraction (SR-PXD) and high-pressure differential scanning calorimetry (HP-DSC). Two routes for synthesis of Mg2FeH6 were studied. The first utilizes a ball-milled homogeneous MgH2-Fe powder mixture and the second uses a mixture of Fe and Mg formed by decomposition of the ternary hydride, Mg2FeH6. In both cases the reaction mixture was sintered in a temperature range from RT to 500 degrees C under a hydrogen pressure of 100-120 bar. The reaction mechanisms were established using in-situ SR-PXD. The formation of Mg2FeH6 consists of two steps with MgH2 as an intermediate compound, and the presence of magnesium was not observed. In contrast, the decomposition of Mg2FeH6 was found to be a single-step reaction. Additionally, both reactions were investigated using HP-DSC under similar conditions as in the SR-PXD experiments in order to estimate reaction enthalpies and temperatures. Mg2FeH6 was found to form from MgH2 and Fe under hydrogen pressure regardless of whether the MgH2 was introduced in the mixture or formed prior to creation of the ternary hydride. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

AB - Synthesis and decomposition mechanisms of ternary Mg2FeH6 were investigated using in-situ synchrotron radiation powder X-ray diffraction (SR-PXD) and high-pressure differential scanning calorimetry (HP-DSC). Two routes for synthesis of Mg2FeH6 were studied. The first utilizes a ball-milled homogeneous MgH2-Fe powder mixture and the second uses a mixture of Fe and Mg formed by decomposition of the ternary hydride, Mg2FeH6. In both cases the reaction mixture was sintered in a temperature range from RT to 500 degrees C under a hydrogen pressure of 100-120 bar. The reaction mechanisms were established using in-situ SR-PXD. The formation of Mg2FeH6 consists of two steps with MgH2 as an intermediate compound, and the presence of magnesium was not observed. In contrast, the decomposition of Mg2FeH6 was found to be a single-step reaction. Additionally, both reactions were investigated using HP-DSC under similar conditions as in the SR-PXD experiments in order to estimate reaction enthalpies and temperatures. Mg2FeH6 was found to form from MgH2 and Fe under hydrogen pressure regardless of whether the MgH2 was introduced in the mixture or formed prior to creation of the ternary hydride. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

KW - High-pressure DSC

KW - (ball) milling

KW - Mechanical

KW - Magnesium-iron ternary hydride

KW - Magnesium hydride

KW - Iron

KW - In-situ synchrotron radiation powder

KW - X-ray diffraction

U2 - 10.1016/j.ijhydene.2010.01.144

DO - 10.1016/j.ijhydene.2010.01.144

M3 - Article

VL - 35

SP - 3578

EP - 3582

JO - International Journal of Hydrogen Energy

JF - International Journal of Hydrogen Energy

SN - 1879-3487

IS - 8

ER -