Determination of the Heat of Hydride Formation/Decomposition by High-Pressure Differential Scanning Calorimetry (HP-DSC)

Abstract

Among the thermodynamic properties of novel materials for solid-state hydrogen storage, the heat of formation/decomposition of hydrides is the most important parameter to evaluate the stability of the compound and its temperature and pressure of operation. In this work, the desorption and absorption behaviors of three different classes of hydrides are investigated under different hydrogen pressures using high-pressure differential scanning calorimetry (HP-DSC). The HP-DSC technique is used to estimate the equilibrium pressures as a function of temperature, from which the heat of formation is derived. The relevance of this procedure is demonstrated for (i) magnesium-based compounds (Ni-doped MgH2), (ii) Mg-Co-based ternary hydrides (Mg-CoHx) and (iii) Alanate complex hydrides (Ti-doped NaAlH4). From these results, it can be concluded that HP-DSC is a powerful tool to obtain a good approximation of the thermodynamic properties of hydride compounds by a simple and fast study of desorption and absorption properties under different pressures.

NiB nanoparticles: A new nickel-based catalyst for hydrogen storage properties of MgH2

“…8. For each curve, the heating process gives rise to only one large endothermic peak belonged to the desorption of MgH 2 , the onset temperature of this peak shifts to higher values from w332 C to w383 C when the hydrogen pressure increased from 2.8 bar to 13.1 bar, the results were consistent with the value of Mg 99 Ni 1 under different H 2 pressures [32]. Similarly, during the cooling process only one exothermic peak related to the absorption of hydrogen in magnesium was observed.…”

Al3Li4(BH4)13: A Complex Double‐Cation Borohydride with a New Structure

“…During the milling process, pressure and temperature were continuously in situ monitored to follow any hydrogen evolution processes (evico magnetics device). [29,30] Transmission X-ray diffraction measurements were done in 0.7 mm capillaries with a STOE Stadi P (Mo Ka ) in Debye-Scherrer geometry with a step size of 0.028 2V at room temperature. The diffractometer is equipped with a curved GeA C H T U N G T R E N N U N G (111) monochromator and a 68 linear position sensitive detector with a resolution of about 0.068 2q at full width at half maximum Synchrotron radiation in situ powder X-ray diffraction (SR-PXD) data of the 1:4 and 1:5 ratios were collected at beamline BM01A at the European Synchrotron Radiation Facility, Grenoble (France).…”

Hydrogen Sorption Cycling Kinetic Stability and Microstructure of Single-Walled Carbon Nanotube (SWCNT) Magnesium Hydride (MgH2) Nanocomposites

“…31 The technique relies on heating the samples at various pressures at a sufficiently slow rate that the onset of desorption occurs at an equilibrium temperature as dictated by the van't Hoff equation: To analyze the released gas and confirm negligible hydrocarbon evolution during dehydrogenation, we combined mass spectroscopy with a thermal gravimetric analyzer and studied the gas evolution. The samples were analyzed on a Netzsch TG/MS/FTIR system (Netzsch TG 209 F1 Iris coupled to an Aëolos QMS403C mass spectrometer and a Bruker Tensor 27 Fourier Transform Infrared spectrometer via a TGA A588 TGA-IR module) under a flow of ultrahigh pure argon (99.9993%) to avoid oxidation during the runs.…”