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Mesoporous chromium( iii) terephthalate MIL-101 was treated with aqueous solutions of sodium fluoride, chloride, and bromide. The properties of the resulting compounds to sorb nitrogen, hydrogen, and methane were studied. The methane sorption was shown to depend on the nature of the inserted halide ion. The treatment with a sodium chloride solution leads to an increase in the methane uptake by MIL-101. [ABSTRACT FROM AUTHOR]

The interaction of mesoporous chromium( iii) terephthalate [Cr3O(C8H4O4)3F(H2O)2] (MIL-101) with an aqueous solution of the anionic cluster [Re4S4F12]4− ({Re4}) afforded a novel hybrid material {Re4}@MIL-101. According to the elemental analysis data, one cavity of the nanoporous framework contains up to two-three tetranuclear rhenium clusters. The hybrid sorbent obtained reversibly absorbs up to 3.7 wt.% hydrogen at 77 K and 30 atm. [ABSTRACT FROM AUTHOR]

The first cycles of hydrogen absorption-desorption in LaNi5-H2 and LaNi4.5Cu0.5-H2 systems were studied using Tian-Calvet differential heat-conduction microcalorimetry, volumetric measurements, and powder X-ray diffraction. The diffraction profiles were analyzed, and the microstructure characteristics of the LaNi5 and LaNi4.5Cu0.5 systems at different stages of activation were determined. The pressure-composition isotherms were plotted, and the enthalpies of phase transitions α→β and β→α were calculated. The effect of substitution on the change in the thermodynamic parameters and microstructure characteristics of the hydride-forming intermetallic compounds during activation was shown. [ABSTRACT FROM AUTHOR]

In order to examine the influence of the production technique on the performance of hydride-forming multi-principal-component alloys, a series of alloys in the Ti–Zr–V–Nb–Ta-Hf system has been obtained by arc-melting and electron beam melting combined with pendant-drop melt extraction (EBM-PDME). Structure analysis shows that EBM-PDME method ensures the synthesis of single-phase alloys with BCC structure for all studied compositions. During hydrogenation, the complete and reversible BCC to FCC phase transformation with maximum hydrogen capacity up to 2.0 wt% occurs. Mechanical and thermophysical investigations demonstrate high values of tensile strength, plasticity and thermal conductivity, which allow the alloys to be used as materials for membrane hydrogen separation. • EBM-PDME method ensures the synthesis of single-phase alloys with BCC structure. • Complete and reversible BCC to FCC phase transformation occurs upon hydrogenation. • Maximum hydrogen capacity reaches 2.0 wt%. • Promising thermal and mechanical properties were found. • Alloys have prospects for use as membrane materials for hydrogen separation. [ABSTRACT FROM AUTHOR]

The single-phase multi-principal-component CoFeMnTiVZr alloy was obtained by rapid solidification and examined by a combination of electrochemical methods and gas-solid reactions. X-ray diffraction and high-resolution transmission electron microscopy analyses reveal a hexagonal Laves-phase structure (type C14). Cyclic voltammetry and electrochemical impedance spectroscopy investigations in the hydrogen absorption/desorption region give insight into the absorption/desorption kinetics and the change in the desorption charge in terms of the applied potential. The thickness of the hydrogen absorption layer obtained by the electrochemical reaction is estimated by high-resolution transmission electron microscopy. The electrochemical hydrogen storage capacity for a given applied voltage is calculated from a series of chronoamperometry and cyclic voltammetry measurements. The selected alloy exhibits good stability for reversible hydrogen absorption and demonstrates a maximum hydrogen capacity of ∼1.9 wt% at room temperature. The amount of hydrogen absorbed in the gas-solid reaction reaches 1.7 wt% at 298 K and 5 MPa, evidencing a good correlation with the electrochemical results., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)