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Abstract: The development of materials showing rapid proton conduction with a low activation energy and stable performance over a wide temperature range is an important and challenging line of research. Here, we report confinement of sulfuric acid within porous MFM-300(Cr) to give MFM-300(Cr)·SO4(H3O)2, which exhibits a record-low activation energy of 0.04 eV, resulting in stable proton conductivity between 25 and 80 °C of >10–2 S cm–1. In situ synchrotron X-ray powder diffraction (SXPD), neutron powder diffraction (NPD), quasielastic neutron scattering (QENS), and molecular dynamics (MD) simulation reveal the pathways of proton transport and the molecular mechanism of proton diffusion within the pores. Confined sulfuric acid species together with adsorbed water molecules play a critical role in promoting the proton transfer through this robust network to afford a material in which proton conductivity is almost temperature-independent.

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Abstract: Solid-state inorganic magnesium batteries are considered as potential high energy storage devices for the future. Here we present a series of magnesium borohydride tetrahydrofuran (THF) composites, Mg(BH 4 ) 2 · x THF(−MgO), 0 ≤ x ≤ 3, as solid-state electrolytes for magnesium batteries. Three new monoclinic compounds were identified, Mg(BH 4 ) 2 ·2/3THF ( Cc ), α-Mg(BH 4 ) 2 ·2THF ( P2 1 /c ) and β-Mg(BH 4 ) 2 ·2THF ( C2 ), and the detailed structures of α− and β−Mg(BH 4 ) 2 ·2THF are presented. The magnesium ionic conductivity of composites formed by these compounds were several orders of magnitude higher than that of the distinct compounds, x = 0, 2/3, 2, and 3. The nanocomposite stabilized by MgO nanoparticles (~50 nm), Mg(BH 4 ) 2 ·1.5THF−MgO(75 wt%), displayed the highest Mg 2+ conductivity, σ(Mg 2+ ) ~10 -4 S cm -1 at 70 °C, a high ionic transport number of t ion = 0.99, and cyclic voltammetry revealed an oxidative stability of ~1.2 V vs. Mg/Mg 2+ . The electrolyte was stable towards magnesium electrodes, which allowed for stable Mg plating/stripping for at least 100 cycles at 55 °C with a current density of 0.1 mA cm -2 . Finally, a proof-of-concept rechargeable solid-state magnesium battery was assembled with a magnesium metal anode, a TiS 2 cathode providing a maximum discharge capacity of 94.2 mAh g -1 , which corresponds to y = 0.2 in Mg y TiS 2.

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Abstract: We report reversible high capacity adsorption of SO2 in robust Zr-based metal-organic frameworks (MOFs). Zr-bptc (H4bptc = biphenyl-3,3’,5,5’-tetracarboxylic acid) shows a high SO2 uptake of 6.2 mmol g-1 at 0.1 bar and 298 K, reflecting excellent capture capability and removal of SO2 at low concentration (2500 ppm). Dynamic breakthrough experiments confirm that the introduction of amine, atomically-dispersed Cu(II) or heteroatomic sulphur sites into the pores enhance the capture of SO2 at low concentrations. The captured SO2 can be converted quantitatively to a pharmaceutical intermediate, aryl N-aminosulfonamide, thus converting waste to chemical values. In situ X-ray diffraction, infrared micro-spectroscopic and inelastic neutron scattering enable the visualisation of the binding domains of adsorbed SO2 molecules and host-guest binding dynamics in these materials at the atomic level. The refinement of pore environment plays a critical role in designing efficient sorbent materials.

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Abstract: We present the synthesis of a novel binary metal oxide material: Ba7Mn4O15. The crystal structure has been investigated by high-resolution powder synchrotron X-ray diffraction in the temperature range of 100–300 K as well as by powder neutron diffraction at 10 and 80 K. This material represents an isostructural barium-substituted analogue of the layered material Sr7Mn4O15 that forms its own structural class. However, we find that Ba7Mn4O15 adopts a distinct magnetic ordering, resulting in a magnetoelectric ground state below 50 K. The likely magnetoelectric coupling mechanisms have been inferred from performing a careful symmetry-adapted refinement against the powder neutron diffraction experiments, as well as by making a comparison with the nonmagnetoelectric ground state of Sr7Mn4O15.

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Abstract: Marine archaeological artefacts contain unexpected compounds due to prolonged exposure to the sea. These can remain dormant and embedded within materials until a change in their surrounding environment, such as exposure to oxygen, prompts a transformation. These changes can pose a problem, as acidic compounds are formed which disintegrate the material, or crystals form which physically break the artefact apart. The extent of these transformations is highly heterogeneous due to its dependence on the ability for oxygen to reach and catalyse these reactions. Additionally, these transformations are heavily dependent on the environment the artefact is exposed to, and the pathways available for ingress, either naturally or through previous degradation. This results in materials with a range of different compounds which are often co-located on the macro, micro and nano-scale. Trying to de-convolute these compounds is challenging, and usually requires a suite of complementary techniques to achieve. Here we report on damaging salts found within marine archaeological bricks and show how it is only possible to qualitatively and quantitatively understand what is present by employing a range of analytical techniques, such as XRD, SEM-EDS and SR-XPD. The marine archaeological bricks studied were found to contain a range of different sulfate-based salts, which had grown crystals in preferred orientations. This provides information which will guide further conservation strategies such as how these bricks are stored, conserved and protected in the future.