Chloride substitution in sodium borohydride

Journal Article · Fri Jul 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.05.030· OSTI ID:21580124

Ravnsbaek, Dorthe B; Rude, Line H ^[1]

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1. Center for Materials Crystallography (CMC), Interdisciplinary Nanoscience Center (iNANO), Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Arhus C (Denmark)

The dissolution of sodium chloride and sodium borohydride into each other resulting in formation of solid solutions of composition Na(BH{sub 4}){sub 1-x}Cl{sub x} is studied. The dissolution reaction is facilitated by two methods: ball milling or combination of ball milling and annealing at 300 deg. C for three days of NaBH{sub 4}-NaCl samples in molar ratios of 0.5:0.5 and 0.75:0.25. The degree of dissolution is studied by Rietveld refinement of synchrotron radiation powder X-ray diffraction (SR-PXD) data. The results show that dissolution of 10 mol% NaCl into NaBH{sub 4}, forming Na(BH{sub 4}){sub 0.9}Cl{sub 0.1}, takes place during ball milling. A higher degree of dissolution of NaCl in NaBH{sub 4} is obtained by annealing resulting in solid solutions containing up to 57 mol% NaCl, i.e. Na(BH{sub 4}){sub 0.43}Cl{sub 0.57}. In addition, annealing results in dissolution of 10-20 mol% NaBH{sub 4} into NaCl. The mechanism of the dissolution during annealing and the decomposition pathway of the solid solutions are studied by in situ SR-PXD. Furthermore, the stability upon hydrogen release and uptake were studied by Sieverts measurements. - Graphical Abstract: Dissolution of sodium chloride and sodium borohydride into each other resulting in formation of solid solutions of composition Na(BH{sub 4}){sub 1-x}Cl{sub x} is studied. Dissolution is facilitated by two methods: ball milling or annealing at 300 deg. C for three days of NaBH{sub 4}-NaCl samples. Sample compositions and dissolution mechanism are studied by Rietveld refinement of synchrotron radiation powder X-ray diffraction data. Highlights: > Studies of dissolution of sodium chloride and sodium borohydride into each other. > Solid state diffusion facilitated by mechanical and thermal treatments. > Dissolution is more efficiently induced by heating than by mechanical treatment. > Mechanism for dissolution studied by Rietveld refinement of in situ SR-PXD data.

• OSTI ID: 21580124
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 7; Other Information: DOI: 10.1016/j.jssc.2011.05.030; PII: S0022-4596(11)00279-9; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANNEALING
DISSOLUTION
HYDROGEN
HYDROGEN STORAGE
RADIATION DOSE UNITS
SI UNITS
SODIUM
SODIUM CHLORIDES
SOLID SOLUTIONS
SOLIDS
SYNCHROTRON RADIATION
UPTAKE
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
ALKALI METALS
BREMSSTRAHLUNG
CHLORIDES
CHLORINE COMPOUNDS
COHERENT SCATTERING
DIFFRACTION
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
HEAT TREATMENTS
HOMOGENEOUS MIXTURES
METALS
MIXTURES
NONMETALS
RADIATIONS
SCATTERING
SODIUM COMPOUNDS
SOLUTIONS
STORAGE
UNITS