B18-Core EXAFS
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Diamond Proposal Number(s):
[36104]
Abstract: Seawater splitting has been considered an environmentally friendly and cost-effective method for hydrogen production. However, developing efficient electrocatalysts capable of enduring the severe corrosive conditions of natural seawaters for extended durations remains a notable technical challenge. Herein, the Ni3S2 supported NiFe oxalate ((NiFe)C2O4/Ni3S2) nanorod arrays were synthesised through hydrothermal and impregnation precipitation methods. Structural and spectroscopic analyses revealed that the (NiFe)C2O4/Ni3S2 catalyst formed an integrated oxide-sulfide interface with coexisting Ni–O/Ni–S coordination. This dual coordination environment, coupled with the presence of Fe in a higher oxidation state, confirmed interfacial electronic reorganization characterized by directional electron transfer from Ni to Fe. The resulting charge transfer pathway enhanced the electron delocalisation between active centers, thereby improving active site utilization. The obtained (NiFe)C2O4/Ni3S2 demonstrated remarkable catalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in a simulated alkaline seawater solution (NaCl + KOH), with overpotentials of 363 mV (HER) and 295 mV (OER) at a current density of 500 mA cm−2 for industrial electrolysis requirements and remarkable stability over 100 h of durability testing. Additionally, the (NiFe)C2O4/Ni3S2 electrode pairs only required a cell voltage of 1.81 V to achieve 100 mA cm−2 with Faradaic efficiency of 98 % in 1.0 M KOH + seawater. This study presents a novel approach for fabricating multifunctional electrocatalysts, providing a promising pathway for advancing seawater electrolysis and supporting the development of cost-effective green hydrogen production technologies.
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Nov 2025
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[22053, 31714]
Abstract: Accurate predictions of the size and morphology of microstructural features, including defects such as porosity, are essential for predicting the performance of engineering components. Although several multiscale approaches exist in the literature, including direct simulations and volume-averaged models, their predictions are limited due to large computational times and relatively low accuracy. This work utilises transfer learning to link the macroscopic field variable distributions to the mesoscale, in order to estimate sub-grid microstructural defects. Specifically, the model parameters are corrected using experimental measurements of sub-grid scale defects. The proposed methodology is illustrated for predicting porosity in an aluminium alloy automotive component produced using high pressure die casting. The model uses a physics-based localised porosity model for combined gas and shrinkage porosity to train an artificial neural network. This trained machine learning model is subsequently re-trained using macroscale field variables and experimental X-ray microtomography porosity measurements from industrial component made using different process conditions. An unseen region of the same component is used for further testing of the performance of the model. The results show good prediction of pore size distribution and location. These results are then used to determine component fatigue life. Thus, a full process-structure-property model is established. The framework has the potential to be applied to a large class of problems involving predictions of microstructural features over entire macroscopic components.
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Nov 2025
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B18-Core EXAFS
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Diamond Proposal Number(s):
[32381]
Abstract: This study aimed at determining Ni and Co leaching kinetics from a New Caledonian laterite in an acidic medium (H2SO4 pH 1.5) and in a reductive environment (addition of SO32− or Fe(II)) at 46 °C. The mineralogical study revealed that Co was mainly carried by Mn oxyhydroxides in the limonite sample. Conversely, Ni was hosted by both Fe and Mn oxyhydroxides. In the presence of a reductive reagent, Mn oxyhydroxides dissolved rapidly compared to goethite, the main Fe oxyhydroxide in the sample. Co, Mn and Ni reductive leaching yields reached 79 %, 83 % and 9 % respectively after 2 days. Based on these results, a Mn oxides concentrate was produced in order to efficiently leach Co while limiting Fe oxyhydroxide dissolution. This concentrate resulted from a combination of particle size and gravity separation steps. The volume/mass of sample was drastically decreased since the mass of the final sample was only 3.3 % of the initial one. Co content increased from 0.16 wt% in the limonite to 2.3 wt% in the concentrate, representing an enrichment factor of 13.8 and recovery yield of 60 %. Co, Mn and Ni leaching yields reached 87 %, 95 % and 80 % respectively in the Mn oxides concentrate leaching experiment. The difference in Ni behaviour was consistent with the mineralogical composition: Ni was mainly carried by the goethite in the laterite, while it was hosted mainly by the Mn oxyhydroxides in the Mn oxides concentrate. This study gives a proof of concept for the development a robust pre-concentration process to recover Co.
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Nov 2025
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Open Access
Abstract: Biofuels are critical drop-in replacement energy sources to support the decarbonisation of hard-to-abate sectors such as aviation and marine shipping. Transesterification of non-edible oils is a well-established route to biodiesel as a versatile liquid transport fuel, but is challenging to scale using existing homogeneous liquid base catalysts. In this work, we report the synthesis, characterisation, and application of silica-supported MgO solid base catalysts for triglyceride transesterification with methanol and highlight the impact of silica pore structure on performance. True liquid crystal templating enables the one-pot synthesis of mesoporous MgO/SBA-15 catalysts with variable Mg content, or hierarchical macroporous–mesoporous MgO/SBA-15 analogues through the addition of polystyrene nanospheres. Both MgO/SBA-15 families exhibit highly ordered pore networks; however, ~280 nm macropores stabilise Mg-O-Si interfacial species even at high Mg loading, in contrast to the mesoporous support that permits sintering of ~14 nm MgO nanocrystals. Hierarchical porous MgO/SBA-15 catalysts exhibit higher specific activity and conversion of tributyrin to methyl butyrate than their mesoporous analogues (3 mmol⋅h−1⋅g−1 versus 2 mmol⋅h−1⋅g−1 at 60 °C and 11 wt% Mg). The magnitude of this rate enhancement increases with triglyceride chain length, being approximately three-fold for trilaurin (C12) transesterification at 90 °C, attributed to superior in-pore mass transport of bulky reactants through the hierarchical porous catalyst.
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Nov 2025
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B16-Test Beamline
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Diamond Proposal Number(s):
[33032]
Open Access
Abstract: This study presents the first demonstration of the use of X-ray diffraction (XRD) to quantify the radial or transverse deformation in Hexcel IM7 PolyAcryloNitrile (PAN)-based carbon fibres at temperatures as low as 200 K (-70 °C). The Coefficient of Thermal Expansion (CTE) is a critical design parameter that needs to be precisely quantified for the next generation of carbon fibre-based Liquid Hydrogen (
) storage tanks for net-zero aviation. This variable quantitatively describes the thermal mismatch between the fibre and the resin that is the driver for microcracking and tank leakage. However, quantification of the CTE of the fibres is experimentally challenging. The results provide unique insights, indicating that the microscopic transverse CTE of the fibre (
) is equal to 26.2 × 10-6 K-1 and is governed by van der Waals forces, similar to those in the basal c-axis (out-of-plane) direction of graphite and the radial direction of multi-wall carbon nanotubes. Taking into account the microcrack-induced relaxation effect reported in polycrystalline graphite, the macroscopic fibre transverse CTE was determined to be 7.86 × 10-6 K-1. XRD data were also collected on Hexcel IM7/8552 Uni-directional (UD) and Quasi-isotropic (QI) composite laminates to investigate the influence of the interaction of the resin matrix with the fibre lattice and the stacking sequence on the development of thermal fibre lattice strain. In the UD laminate, the presence of resin induces an additional transverse strain in the fibres as a result of resin contraction during cooling, leading to the development of a compressive strain in the fibre direction. This behaviour was found to be in good agreement with numerical simulations, with a 13 % error at the lowest measured temperature. In contrast, the fibres in the QI configuration were reinforced in the transverse direction, effectively mitigating the influence of resin contraction. These CTE values, insights, and resulting models are essential for multi-scale modelling, design and certification of carbon fibre composite
tanks that are required to achieve net-zero aviation.
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Oct 2025
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[32708]
Open Access
Abstract: BCC superalloys are a promising class of high-temperature materials with a wide range of lattice misfit values, ranging from near-zero to ∼8 %. Analogous to nickel superalloys, lattice misfit combined with elastic anisotropy dictates precipitate morphology (spherical, cuboidal, plate/needle-like), coarsening kinetics, strengthening mechanisms, and microstructure evolution, making misfit control critical for tailoring microstructural stability and creep resistance. However, misfit characterisation, especially at high temperatures, is still in its infancy to establish its links with mechanical properties. This perspective emphasises three aspects of BCC superalloys: representative misfit-driven microstructures and temperature-dependent misfit evolution, state-of-the-art diffraction techniques for high-temperature misfit quantification, and machine learning frameworks to accelerate alloy design involving misfit. By consolidating diverse misfit data and advanced characterisation/modelling strategies, we outline strategies to bridge computational and experimental gaps, advocating for physics-informed models and high-throughput techniques to design next-generation BCC superalloys and motivate systematic studies on the misfit-property relationship in this nascent material class.
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Oct 2025
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B16-Test Beamline
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Diamond Proposal Number(s):
[30528]
Open Access
Abstract: This paper demonstrates a new approach that exploits both lattice strain mapping via Wide Angle X-ray Scattering (WAXS) and Digital Volume Correlation (DVC) of Computed Tomography (CT) to understand the material response at different length scales in Carbon Fibre Reinforced Polymers (CFRPs) under in-situ loading, a phenomenon of substantial importance for the modelling, design, and certification of composite structures. WAXS gives insight into fibre lattice strain, while DVC provides sub-laminate response in the CFRP. A detailed numerical simulation was also developed to compare with these novel experimental methods. This approach is the first demonstration that the strain within the crystalline regions of the fibre is distinct from the sub-laminate behaviour, with up to 80 % and 36 % differences in the longitudinal and transverse directions, respectively, as a result of the complex microstructure of the fibres. An improved understanding of composite behaviour is fundamental to understanding how strain accommodation leads to structural failure, providing routes to refine part rejection criteria and reduce the environmental impact of this increasingly widespread material class.
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Oct 2025
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B16-Test Beamline
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B.
Cline
,
D.
Banks
,
M.
Bishop
,
A.
Davis
,
J.
Harris
,
M.
Hart
,
S.
Knowles
,
T.
Nicholls
,
J.
Nobes
,
S.
Pradeep
,
M.
Roberts
,
M. C.
Veale
,
M. D.
Wilson
,
V. P.
Dhamgaye
,
O. J. L.
Fox
,
K. J. S.
Sawhney
,
S.
Scully
Diamond Proposal Number(s):
[36472]
Open Access
Abstract: In this paper, results are presented from the characterisation of a 2 mm thick Redlen Technologies high-flux-capable Cadmium Zinc Telluride (HF-CZT) sensor hybridised to the small-pixel, spectroscopic-imaging HEXITEC_MHz ASIC. Dynamic datasets were taken on the B16 Test Beamline at the Diamond Light Source to study a previously-identified 'excess-leakage-current' phenomenon in HF-CZT, where additional leakage current was temporarily generated upon the application of an X-ray flux. A study of the response of the detector as a function of X-ray intensity demonstrated a measurable excess leakage current signal above 105 ph s-1 mm-2. At a 20 keV flux of 7.81 × 106 ph s-1 mm-2, this effect contributed a signal equivalent to 3.79 ± 1.59 nA mm-2in addition to the expected photocurrent. On removal of X-rays at this flux, this excess leakage current took ∼ 10 s to decay below the noise floor of the detector. This long lifetime has implications for detectors required to operate at high frame rates and fluxes. The use of a small-pixel detector also allowed the spatial variation of this effect to be studied. A per-pixel comparison between the magnitude of the excess leakage current and the spectroscopic performance of the pixel showed no correlation. This suggests that the phenomenon is less likely to be a bulk-crystal effect and more likely the result of the properties of the CZT surface or metal/semiconductor interface. An Arrhenius analysis of the temperature-dependence of the dark and excess leakage currents in the detector yielded values of 0.69 ± 0.04 eV and 0.13 ± 0.01 eV respectively. The change in dark current with temperature is consistent with deep levels pinning the Fermi level close to the mid band gap, whilst the activation energy of the excess leakage current suggests shallower defects at the metal-semiconductor interface are responsible.
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Oct 2025
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I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[32728]
Open Access
Abstract: Certain members of the bacterial cytochrome P450 152 family (CYP152) are peroxygenases that catalyse the decarboxylation of fatty acids into terminal olefins making them attractive biocatalysts for biofuel production. To date, the characterisation of decarboxylating CYP152s has mainly focused on their reaction with saturated fatty acid substrates. CYP152s are often co-purified with a bound substrate, which is generally removed before further experiments are conducted. In the present work we identified that heterologous over-expressed CYP152 from Staphylococcus aureus (OleTSa) is co-purified with the trans-monounsaturated C18:1 fatty acid, elaidic acid. We report the spectral, thermodynamic and kinetic characteristics of OleTSa bound to both elaidic acid and its saturated counterpart, stearic acid. Despite differing spectral profiles, metabolic and kinetic studies reveal that OleTSa is capable of decarboxylating elaidic acid, converting it to heptadeca-1,8-diene following addition of hydrogen peroxide, at the same rate and chemoselectivity as the conversion of stearic acid to 1-heptadecane. The X-ray crystal structure of the as purified OleTSa in complex with elaidic acid is also presented, allowing for several key residues to be identified for site-directed mutagenesis studies. The influence of the site-directed variants on C18:0 and C18:1 product formation, binding thermodynamics and kinetics have been investigated, showing that while spectral differences occur as a likely result of perturbing the binding pocket, this does not alter the chemoselectivity of the enzyme. Our work provides important insights into the mechanism of decarboxylation of an unsaturated fatty acid substrate by OleTSa potentially expanding the sustainable substrate space available for CYP152s.
Graphical abstract
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Oct 2025
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I19-Small Molecule Single Crystal Diffraction
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Thien D.
Duong
,
Jiangnan
Li
,
Ruohan
Li
,
Xin
Lian
,
Yinlin
Chen
,
Jiarui
Fan
,
Joseph
Hurd
,
Lixia
Guo
,
Daniel
Lee
,
Mark
Warren
,
Sihai
Yang
Diamond Proposal Number(s):
[41123]
Abstract: The capture of xenon (Xe) and krypton (Kr) from the off-gas of used nuclear fuel is of great importance to the treatment of radioactive wastes and production of high purity Xe. Solid sorbents, in particular metal–organic frameworks (MOFs), show promise in gas capture. However, the unknown radiation resistance of MOFs has limited their development. Herein, the efficient capture and separation of Xe/Kr by MFM-520, which strikes a remarkable stability toward 1750 kilogray (kGy) γ-irradiation, is reported. Under ambient conditions, dynamic breakthrough experiments confirm the efficient separation performance, yielding a Xe capacity of 66 and 0.2 mg g−1 from a by-product of air separation (Xe/Kr: 20/80; v/v) and off-gas (Xe/Kr: 400/40 ppm balance in air), respectively. In situ synchrotron X-ray single crystal diffraction and solid-state nuclear magnetic resonance (ssNMR) studies reveal that the optimal micropore of MFM-520 underpins specific host-guest interactions to Xe, resulting in selective Xe capture.
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Oct 2025
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