I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[33667]
Open Access
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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Mar 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[25166]
Open Access
Abstract: The crystallization of a trimetallic cobalt–molybdenum–sodium metal–organic framework, poly[μ-benzene-1,3,5-tricarboxylato-tetra-μ-oxido-cobaltmolybdenumtrisodium], UOW-10 or [Na3Co(MoO4)(BTC)]n, is achieved by solvothermal synthesis using benzene-1,3,5-tricarboxylic acid (H3BTC, C9H6O6) as a ligand precursor, Na2MoO4·2H2O and Co(NO3)2·2H2O as metal sources, and N,N-dimethylformamide (DMF) as the solvent. 3D electron diffraction (3D ED) reveals that the structure crystallizes in the monoclinic space group P21/c, with lattice parameters of a = 9.718 (2), b = 18.250 (3), c = 6.892 (9) Å, α = γ = 90, β = 96.156 (15)°, V = 1214.7 (4) Å3 and Z = 4. The phase purity of the bulk sample was confirmed using synchrotron powder X-ray diffraction. The organic ligands form a 2D layer, where cobalt and molybdenum are found, with sodium cations located between the layers. There are four crystallographically distinct sodium sites: three exhibit a distorted octahedral coordination geometry, while the remaining site is seven-coordinate. The cobalt has trigonal bipyramidal coordination geometry and molybdenum exhibits a tetrahedral coordination geometry. Half the sodium cations in the structure forms 1D column-like motifs via shared oxygen edges along the crystallographic c axis, which are cross-linked in b by the cobalt and molybdenum sites via bridging O atoms, while the other half of the sodium cations form 2D ribbons in the ac plane, propagating along c, linked by sharing oxygen edges and faces. The optical properties of UOW-10 were investigated through the use of UV–Vis spectroscopy, showing a bandgap of 1.8 eV. Deconvolution of the features in the visible-light region reveals that four peaks are present, which can all be ascribed to the d–d transitions from the trigonal bipyramidal cobalt. By means of thermogravimetric analysis (TGA) and variable-temperature powder X-ray diffraction (VT-PXRD), it is demonstrated that the material has thermal stability to 410 °C, after which structure collapse occurs, leading to a mixture of Na2MoO4, CoO and Co3Mo above 900 °C.
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Mar 2026
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Shan
Dai
,
Xiangdi
Zeng
,
Benjamin J.
Moore
,
Yuxiang
Zhu
,
Yuhang
Yang
,
Zi
Wang
,
Luyan
Li
,
Te
Wang
,
Ivan
Da Silva
,
Luke
Keenan
,
Floriana
Tuna
,
Daniel
Lee
,
Sarah
Day
,
Lucy
Saunders
,
Martin
Schroeder
,
Sihai
Yang
Abstract: Metal–organic framework (MOF) materials share some common features with metalloenzymes including site-isolated metal centers that template dynamic substrate activation within a functionalized cavity or pocket. We report the light-induced reversible binding of CO2 in a cerium-based MOF, Ce-UiO-66-NH2, incorporating an amino functionalized linker, which enables photoreduction of CO2 to CO in H2O without using sacrificial agents. A production rate for CO of 126 μmol·g–1·h–1 with 100% selectivity is observed, outperforming its non-amine analogue (Ce-UiO-66) and benchmark catalysts reported to date. In situ infrared, X-ray absorption, electron paramagnetic resonance and transient absorption spectroscopy reveal that photoexcitation induces a ligand-to-metal charge transfer to generate transient open Ce(III) sites that bind CO2 in a μ-(η1-O)(η1-C) binding mode. This binding is reversible and activates CO2 for subsequent photoreduction to CO. This work will promote the design of photocatalysts capable of synthesizing fuels from CO2.
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Mar 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[32708]
Open Access
Abstract: Next-generation concentrated solar power (CSP) systems place stringent demands on structural materials that must operate reliably at temperatures exceeding 800 °C. Chromium-based BCC-superalloys strengthened by B2-NiAl intermetallic compounds are promising candidates for meeting these high-temperature requirements. Previous studies on Cr-5Ni-5Al and Cr-5Ni-5Al-10Fe (at.%) alloys have shown only a modest volume fraction of ~5% B2-NiAl precipitates. This work aims to increase the intermetallic volume fraction and assess the resultant microstructure and mechanical properties. Phase diagram calculations (CALPHAD) revealed that the addition of 20 at.% Fe allows for complete homogenisation of Cr-10Ni-10Al into single phase (A2) at 1400 °C. Ageing treatments at 800, 1000 and 1200 °C produced coherent B2-NiAl precipitates, reaching a maximum area fraction of ~16% at 1200 °C for 20 h, which is a net increase over previously achieved 5% inCr-5Ni-5Al-10Fe. The precipitates grew via a diffusion-controlled process with exceptionally low coarsening rates. Synchrotron X-ray diffraction results confirmed low lattice misfit ~ −0.1% in the Cr-10Ni-10Al-20Fe alloy. Furthermore, microhardness measurements demonstrated that the combined effects of Fe solid solution strengthening and enhanced B2 precipitation strengthening yield superior hardness in Cr-10Ni-10Al-20Fe alloy at room temperature compared to Cr-10Ni-10Al ternary alloy for the vast majority of heat treatment temperatures. These findings provide guidance for designing Cr-based BCC-superalloys with thermal stability and mechanical robustness for service in demanding high-temperature energy-conversion environments.
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Mar 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[16358]
Open Access
Abstract: In aluminosilicate zeolites, the atomic-scale insights into catalytic performance are tied to Brønsted acid sites (BASs), the primary active sites generated by the substitution of aluminum (Al) for silicon (Si) in the tetrahedral framework, with a proton (H⁺) compensating for the resultant charge imbalance. The profound influence of Al distribution on BAS density, spatial arrangement, and acidity is well established. Yet, the precise atomic positions of these Al atoms remain poorly resolved. Using silver (Ag) as a molecular probe, this study combines synchrotron X-ray diffraction (SXRD) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) to reveal the specific locations of Al atoms in ZSM-5, a prototypical zeolite catalyst. Statistical analysis of HAADF-STEM images unambiguously identifies the crystallographic adsorption sites of Ag at T4, T6, and T8, linking their distribution directly to the predominant framework Al sites, which correlates perfectly with the predominant Al sites identified by our previous work. By mapping these Al sites, we establish an atomic-scale model for single atom catalysis within the zeolite framework. This work develops methodologies further to elucidate the structure-activity relationship of industrially relevant zeolite catalysts, providing the foundational knowledge for rationally designing zeolite catalysts with optimised active sites and enhanced performance.
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Mar 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[39378]
Open Access
Abstract: We discover a rare structural manifestation of the Goldstone paradigm in a hexagonal polytype of the prototypical ferroelectric BaTiO3. First-principles calculations confirm the Goldstone character of the order parameter, while our high-resolution diffraction measurements unveil an unusual reentrant Goldstone regime manifesting as a quasicontinuous domain texture in the vicinity of the ferroelectric transition. We develop a minimal Landau model that encapsulates these observations, illustrating how U(1) symmetry can be restored at the ferroelectric transition. Our findings demonstrate how exotic Goldstone physics can be unlocked in systems dominated by highly anharmonic interactions, presenting a promising pathway to stabilize emergent polar topologies in bulk materials.
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Mar 2026
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I11-High Resolution Powder Diffraction
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Haowen
Tian
,
Li
Tianyu
,
Anya S.
Mulligan
,
Jack P. G.
Tregidga
,
Matthew A.
Wright
,
Zohar
Arava
,
Chezhiyan
Aditya
,
Molleigh B.
Preefer
,
Stone
Kevin H
,
Jerry
Hu
,
Guang
Wu
,
Alicia María
Manjón-Sanz
,
Saul H.
Lapidus
,
John W.
Harter
,
Anthony K.
Cheetham
,
Ram
Seshadri
Diamond Proposal Number(s):
[36397]
Abstract: A previously unreported low-temperature phase transition in bismuth halide double perovskite Cs2AgBiCl6 is reported, thereby establishing trends in the structural ground states across Cs2NaBiCl6, Cs2AgBiCl6, and Cs2AgBiBr6. Using the combined toolkit of variable-temperature synchrotron X-ray and neutron powder diffraction, Raman spectroscopy, and density-functional theory-based electronic structure modeling, we demonstrate a cubic
𝐹𝑚3¯𝑚→
tetragonal I4/m transition upon cooling with distinct onset temperatures. Neutron powder diffraction refinements and DFT calculations assign the low-temperature phase of Cs2NaBiCl6 to I4/m, rather than the previously reported I4/mmm ground state. Cs2AgBiCl6 is also found to transform to a structure crystallizing in the I4/m space group at low temperatures. Temperature-dependent Raman data and density-functional-theory-based modeling capture the softening and freezing of octahedral tilt modes and quantify relative instabilities. Solid-state nuclear magnetic resonance spectroscopy at room temperature completes the characterization and helps underpin the subtle differences in the covalency across the compounds. Trends in the phase transition temperature Ts and tilt magnitudes emerge from coupled effects of halide identity, M(I)–site bonding character, and a mismatch between interatomic distances. These results establish the structure–dynamics–bonding framework for tuning tilt-driven instabilities in halide double perovskites.
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Mar 2026
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I11-High Resolution Powder Diffraction
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Ragnar
Strandbakke
,
Sebastian Lech
Wachowski
,
Maria
Balaguer
,
Lasse
Vines
,
Thomas Neset
Sky
,
Iga
Szpunar
,
Patricia A.
Carvalho
,
Aleksandra
Mielewczyk-Gryń
,
Magnus H.
Sørby
,
Maria
Gazda
,
Jose M.
Serra
,
Truls
Norby
Open Access
Abstract: Proton ceramic electrochemical cells PCECs hold promise for efficient, sustainable production and use of hydrogen. The positive electrodes are mixed proton conducting perovskites that facilitate water splitting and oxygen reduction, but the factors that determine the protonation are poorly understood. Here, we establish the governing principles of protonation through a study of hydration of 45 double perovskites with the general formula , having Ba or Ba+Sr on AI and a mix of rare earths (Y and lanthanides Ln = La, Pr, Nd, Sm, Gd, Dy, Tb, Lu) on AII. We show how hydration is coupled to the A-site basicity and disorder as well as population of electron holes in the Co-O bond (Co oxidation state), promoted by a closed or semi-closed Ln 4 f shell, i.e., Ln = La, Gd, Lu.
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Mar 2026
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I11-High Resolution Powder Diffraction
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Brinda
Kuthanazhi
,
Debalina
Banerjee
,
Dmitry
Maslennikov
,
Andrij
Vasylenko
,
Jan P.
Scheifers
,
Cara J.
Hawkins
,
Daniel
Ritchie
,
Craig M.
Robertson
,
Marco
Zanella
,
Troy D.
Manning
,
Luke M.
Daniels
,
Marina R.
Filip
,
Matthew S.
Dyer
,
Laura M.
Herz
,
John B.
Claridge
,
Matthew J.
Rosseinsky
Diamond Proposal Number(s):
[37989]
Open Access
Abstract: We explore multiple-cation chalco–halide phase fields evaluated by their synthetic accessibility using machine learning models. Exploratory synthesis guided by computational tools leads to the discovery of two new compounds; CuSn2SI3 and Cu0.35Sn5.29S2I7, their structures, and electronic and optical properties are reported herein. This is the first report of a stable quaternary compound in the Cu–Sn–S–I phase field. The two new compounds show related crystal structures where Sn4S2I4 layers are a common structural motif in both. These Sn4S2I4 layers are connected by Cu2I2 layers and disordered Cu–Sn–I layers, forming the three-dimensional structures of CuSn2SI3 and Cu0.35Sn5.29S2I7 respectively. Electronic band structure calculations using density functional theory show the presence of a direct band gap in CuSn2SI3 and suggest anisotropic transport, in line with the layered structure of the compound. A mixture of the two compounds with ∼86% CuSn2SI3, shows a band gap in the visible region, close to 2.1 eV and a significant photo-induced charge carrier mobility of ∼1.3 cm2 V−1 s−1. This demonstrates Cu–Sn chalco–halides can form a promising phase space to explore for solar absorber materials, with further design and tuning of band gap.
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Mar 2026
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[32893]
Open Access
Abstract: The crystal and magnetic structures of Sr3Fe4O6S2 (= Sr3Fe2O5Fe2OS2) and Sr4Fe4O7S2 (= Sr4Fe2O6Fe2OS2), designed using a building-block approach, are reported. They are fully charge-ordered with Fe2+ and Fe3+ ions in distinct layers showing independent long-range magnetic order. Complex microstructures in some regions suggest new targets.
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Feb 2026
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