In situ X-ray diffraction environments for high-pressure reactions

Abstract

New sample environments and techniques specifically designed for in situ powder X‐ray diffraction studies up to 1000 bar (1 bar = 105 Pa) gas pressure are reported and discussed. The cells can be utilized for multiple purposes in a range of research fields. Specifically, investigations of gas–solid reactions and sample handling under inert conditions are undertaken here. Sample containers allowing the introduction of gas from one or both ends are considered, enabling the possibility of flow‐through studies. Various containment materials are evaluated, e.g. capillaries of single‐crystal sapphire (Al2O3), quartz glass (SiO2), stainless steel (S316) and glassy carbon (Sigradur K), and burst pressures are calculated and tested for the different tube materials. In these studies, high hydrogen pressure is generated with a metal hydride hydrogen compressor mounted in a closed system, which allows reuse of the hydrogen gas. The advantages and design considerations of the in situ cells are discussed and their usage is illustrated by a case study.

Mg-based compounds for hydrogen and energy storage

“…The activation energies extracted for the air-exposed samples may be assumed to be maximum values, which may be relevant to know for practical applications. This work also illustrates that in situ synchrotron radiation powder X-ray diffraction (SR-PXD) is a useful technique for investigation of kinetic properties [40,41]. These results indicate that the presence of either Mg 2 Cu or MgCu 2 in MgH 2 has a pronounced positive effect on the dehydrogenation kinetics of air-exposed samples.…”

Review of magnesium hydride-based materials: development and optimisation

“…Upon decomposition, Nb 2 O 5 may form ternary Mg-Nb oxides, which are suggested to facilitate hydrogen diffusion through the surrounding magnesium oxide surface layer [97][98][99]. The effect of Nb 2 O 5 for hydrogen release and uptake in the Mg/ MgH 2 system has been investigated using in situ SR-PXD [100,101] of three MgH 2 -Nb 2 O 5 (8 mol %) samples continuously ball-milled to different extents during up to eight full hydrogen release and uptake cycles [102]. The aim of this study was to explore the chemical reactions in the system Mg-MgH 2 -Nb 2 O 5 with relative large amounts of additive and to develop further knowledge on the superior properties of niobium pentoxide as an additive.…”

Hydrogen storage properties of nanoconfined LiBH 4 –NaBH 4

“…I.D. ), in an airtight sample holder inside an argon filled glovebox [37]. The sample holder was removed from the glovebox and attached to a gas control system at the synchrotron diffractometer.…”