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Abstract: The use of conventional zirconium alloys at temperatures above 400 °C is limited by high temperature strength and creep resistance. This has prevented the consideration of zirconium alloys for fusion and Generation IV fission plant designs operating at 500 °C–1000 °C. The physical metallurgy of zirconium is similar to titanium which has seen alloying advances allowing application temperatures up to 600 °C. Although the oxidation resistance of zirconium-based alloys is expected to be poor, in a water environment, new Generation-IV and fusion reactors are designed to operate using alternative coolants such as liquid metals and molten salts. Therefore, a new class of zirconium alloys in the Zr-Al-Sn-(Si,Cr,V) system, designed by analogy to near- titanium alloys, were synthesised by arc melting and processed in a sequence of homogenisation, hot/cold rolling, recrystallisation, and ageing treatments. Microscopy and diffraction identified a refined fully lath grain structure reinforced by nanoscale lamellar or discrete coherent Zr3Al precipitates, with morphology and crystal structure differing with ageing times. Additionally alloying with Si, Cr, and V respectively leads to Zr2Si, ZrCr2, and ZrV2 incoherent precipitates. Tensile testing revealed a strengthening effect by Al, but with significant changes to ductility on ageing depending on the evolution of Zr3Al. Creep testing showed creep rates orders of magnitude better than conventional Zircaloy-4 and nuclear ferritic/martensitic steels, approaching near- Ti alloys. The present work offers new insights and perspectives into how high-temperature zirconium alloys might be designed to meet the requirements for fusion and Gen-IV fission.

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Abstract: Fluorination of the n = 2 Ruddlesden–Popper oxide, La3Ni2O7, with polyvinylidene fluoride yields La3Ni2O5F4, a phase in which fluoride ions have been inserted into interstitial sites in the Ruddlesden–Popper framework and also exchanged with the oxide ions residing on apical anion sites. Reaction with LiH at 190 °C reduces La3Ni2O5F4 by extracting interstitial fluoride ions. The resulting phase, La3Ni2O5F3, adopts a structure described in space group Pbcm in which the fluoride ions in the half-filled interstitial layer are arranged in chains parallel to the y-axis, and the NiO5F octahedra adopt an a–a–c+/–(a–a–)c+ tilting pattern. Further reduction with LiH at 250 °C converts La3Ni2O5F3 into La3Ni2O5F, a Ni1+ phase which adopts a T′-structure consisting of double infinite-sheets of apex linked NiO4 squares, stacked with LaOF fluorite-type layers. Magnetization and neutron diffraction data indicate La3Ni2O5F3 adopts an antiferromagnetically ordered state below TN = 225 K, while magnetization data from La3Ni2O5F exhibit a broad maximum centered at 75 K, suggestive of antiferromagnetic order.

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Abstract: Lanthanide borates are widely studied for their optical and magnetic properties. A wide variety of structures are known with 3, 2, 1 and 0 dimensional connectivity of lanthanide ions. Here, we explore MgO10, with a quasi-1D arrangement of the Ln ions. Polycrystalline samples of MgO10 (Ln = La, Pr, Nd, Sm–Er) were synthesised via a solution-based method, which achieved higher purity than a solid-state method. Powder x-ray diffraction data confirmed the reported monoclinic space group (). The magnetic ions in MgO10 form relatively isolated zig-zag chains parallel to the b axis. Magnetic susceptibility and isothermal magnetisation were measured: all samples except (Eu, Sm) fit the Curie-Weiss Law in isothermal magnetisation at high temperatures, in broad agreement with theoretical expectations. (Nd, Tb, Dy, Ho, Er) exhibit signatures characteristic of Ising spin saturation, implying single ion anisotropy, while Gd exhibits characteristics of Heisenberg spins. Estimation of magnetic interactions suggests that MgO10 are candidate materials for quasi-1D magnetism. The magnetocaloric entropy change was also calculated, with MgGdB5O10 showing promise for application to solid-state refrigeration at liquid helium temperatures.

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Abstract: Although it is widely accepted that the long-range (average) crystal structure plays a critical role in determining the electrochemical performance of battery materials, the relationship between local structural features and electrochemical performance is rarely studied. Disordered rock salt oxides (DRX), which have become serious contenders for next generation Li-ion electrode materials, provide an ideal platform for exploring correlations between local structure and electrochemical performance as they exhibit a simple face-centered cubic structure and combine long-range disorder and short-range order on the cation sublattice. This work examines the Li1.1Mn0.7Zr0.2−xTixO2 series of DRX cathodes and investigates the links between local structure rearrangements and capacity activation. The end-member Li1.1Mn0.7Zr0.2O2 compound exhibits a low capacity in the as-synthesized state, attributed to unfavorable short-range order that hinders Li-ion transport, yet its capacity increases seven-fold, from 20 to 140 mAh g−1, after chemical delithiation followed by a 400 °C heat treatment. Capacity activation is associated with the appearance of local spinel-like structural features that depart from the short-range order originally present in the material, without significant change to the bulk composition and average crystal structure. Investigation of a series of Li1.1Mn0.7Zr0.2−xTixO2 (x ≤ 0.2) DRX compounds reveals that the correlation length of the spinel-like ordering that emerges during the heat treatment strongly depends on the Zr[thin space (1/6-em)]:[thin space (1/6-em)]Ti ratio. Yet, dramatic capacity activation and electrochemical (pseudo-)plateaus reminiscent of Mn-based spinel cathodes are observed for all compounds irrespective of the size of the ordered domains. To explain this phenomenon, we propose that the DRX phase undergoes a complete transformation to a spinel-like domain structure, which improves bulk Li-ion transport regardless of domain size.

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Abstract: Catalytic hydrodeoxygenation (HDO) is critical for bio-oil upgrading, yet the selective cleavage of stable C(sp2)–OH bonds in lignin-derived substrates under aqueous conditions remains a challenge. Here, we report a heteroatomic zeolite catalyst, RuFA/SAPO-34-Nb, featuring few-atom Ru clusters on a Nb(V)-modified SAPO-34 framework, which achieves highly efficient HDO of lignin-derived creosol (2-methoxy-4-methylphenol) in water. Under mild conditions (250 °C, 7 bar H2, 24 h), this catalyst delivers quantitative conversion of creosol to toluene (99.2% conversion, 99.6% selectivity), fully preserving the aromaticity of lignin-derived feedstocks─a key requirement for sustainable production of chemicals. Synchrotron X-ray diffraction, X-ray absorption spectroscopy, and inelastic neutron scattering, combined with theoretical modeling, elucidate the cooperative mechanism: the Nb(V) sites selectively cleave the strong C–O bonds, while the few-atom Ru cluster generates hydrogen species with an exceptionally low rotational barrier of 65 cm–1. This synergistic interaction enables the direct and selective HDO of C(sp2)–O bonds without saturation of the aromatic ring. This work establishes a promissing strategy for aqueous-phase HDO catalysis and provides a general approach for designing bimetallic zeolite catalysts to convert lignin-derived compounds to value-added aromatic chemicals, advancing sustainable biorefinery processes.