B23-Circular Dichroism
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Diamond Proposal Number(s):
[36624, 38372]
Open Access
Abstract: Binary mixtures of the ferronematic liquid crystal DIO with the recently reported LC non-ferroelectric material WJ-16 exhibiting Colossal Permittivity (CP) ≈ 5000 and superparaelectricity were studied by POM, electrical switching studies, and dielectric spectroscopy. Three mixtures with different WJ-16 contents ranging from 10, 25 to 50% (w/w) in DIO as host were prepared. Our original expectation was the observations of new nematic compositions with both ferroelectric nematic (N F ) and non-ferroelectric CP phases. We found that the non-ferroelectric phase in mixtures exhibits a CP mode, originally observed in pure WJ-16. The dielectric spectroscopy of mixtures shows two distinct relaxation processes: the typical paraelectric response and the CP mode. Therefore, this CP mode in the mixtures is not superparaelectric and here it is defined as a Hyper-dielectric mode. This is the first direct demonstration of mixtures having both ferroelectric and hyper-dielectric phases in liquid crystalline materials.
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Feb 2026
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B21-High Throughput SAXS
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Open Access
Abstract: The fabrication of superlattices is nontrivial because nanoparticles are notoriously difficult to employ due to the complex nanoscale forces among them. An effective way to manipulate these nanoscale forces is to use a soft corona around the solid core. The soft corona can be engineered to alter the forces between nanoparticles—either attracting or repelling them, and thereby influence their self-assembly process. Here, a deep analysis is proposed on how amines of different lengths (C8 to C18) can influence the hierarchical superlattice organization of cerium oxide nanoparticles, from both structural and energetic perspectives, and the consequent optical properties. The aim is to demonstrate how it is possible to shift from disordered to ordered aggregates and how to obtain one structure instead of another by modulating the geometrical and energetic parameters of soft corona/solid core nanoparticles. The results show that organic coating plays a key role in the self-aggregation process of superlattices with advanced optical properties, thereby broadening the range of potential applications for nanoparticles.
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Feb 2026
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
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Diamond Proposal Number(s):
[40403]
Open Access
Abstract: γ-Valerolactone (GVL) is a valuable bio-based chemical, solvent and fuel additive derived from levulinic acid, a key platform chemical from lignocellulosic biomass. Catalytic transfer hydrogenation (CTH) of levulinic acid using secondary alcohols as hydrogen donors presents a sustainable alternative to conventional hydrogenation with molecular hydrogen and can be efficiently carried out with inexpensive oxides. Here, we demonstrate how controlled silica incorporation onto zirconia provides a route to tailor acidity and thus direct reactivity in the CTH of levulinic acid and its esters to GVL. Silica-doped zirconia catalysts with varying Si loadings were synthesised via colloidal deposition and comprehensively characterised using ICP-OES, TEM/EDX, XRD, BET, NH3-TPD, pyridine-adsorbed DRIFTS, XPS and NEXAFS. Moderate silica incorporation enhanced surface area, stabilised the tetragonal ZrO2 phase, and increased total acidity, and most importantly, altered the Brønsted-to-Lewis acid balance that dictated the reactivity. Ethyl levulinate conversion was favoured over Lewis acid-rich catalysts, whereas LA conversion required higher Brønsted acidity. The optimal catalyst (6 wt% Si) delivered 80% GVL yield from levulinic acid at 190 °C in 4 hours. Isopropyl levulinate was identified as a side-product that can also convert to GVL via CTH, though less efficiently. The 6 wt% Si/ZrO2 catalyst exhibited excellent stability across three consecutive cycles without calcination, demonstrating resistance to leaching, a major drawback of heterogeneous catalysts in liquid-phase reactions, as well as to carbon deposition. This study demonstrates that silica doping provides an effective means of tuning zirconia acidity, resulting in catalysts that combine good stability with practical applicability in sustainable chemistry.
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Jan 2026
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B18-Core EXAFS
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Diamond Proposal Number(s):
[37458]
Open Access
Abstract: Geopolymers are a promising alternative to conventional Portland cement-based wasteforms for immobilising hazardous radioactive fission products such as caesium-137 and strontium-90, offering superior durability and lower leach rates. However, the specific mass transport mechanisms governing radionuclide release in geopolymers remain poorly understood, limiting implementation. This study reveals the incorporation and mass transport mechanisms of caesium and strontium in metakaolin-based geopolymers. Solid-state characterisation showed Sr incorporation via direct chemical binding in the chemical binding in the alkali aluminosilicate hydrate gel in chargebalancing extra-framework sites, replacing K + ions, and precipitation of SrCO 3 and Sr(OH) 2 , while Cs is predominantly bound within the charge-balancing sites in the alkali aluminosilicate gel. Leach testing confirmed low overall release rates, with all measured Leachability Indices significantly exceeding the industry minimum of 6 (Li > 13 for Cs; Li > 18 for Sr), outperforming conventional PC systems. Mass transport modelling revealed distinct mechanisms: Cs release is accurately described by a Diffusion/Surface Exchange Kinetics Model (DSEM), yielding high correlation (R 2 > 0.99). However, Sr exhibited a complex, staggered release profile. Standard mass transport models (diffusion, dissolution, surface exchange) could not satisfactorily capture this complex behaviour. We hypothesise this rate resumption is caused by the structural reordering or crystallisation of the amorphous K-A-S-H gel into a zeolitic phase, potentially excluding incorporated Sr. This finding highlights that simple diffusive models, commonly assumed for geopolymers, are inadequate for predicting the long-term per-1 formance of Sr-containing geopolymer wasteforms. The new insight presented here is critical development of geopolymers for radioactive waste disposal.
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Jan 2026
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I15-Extreme Conditions
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Diamond Proposal Number(s):
[36011]
Open Access
Abstract: The development of high-performance lead-free piezoelectric materials has gained significant attention due to environmental concerns regarding lead toxicity. In this study, through in-situ poling synchrotron X-ray diffraction (XRD), dielectric spectroscopy, and ferroelectric measurements, we demonstrate an irreversible transition from non-ergodic relaxor behaviour to long-range ferroelectric ordering under applied electric fields in (1-x)BiFeO3 -xSrTiO3 with MnO2 addition (BF-ST-Mn).The optimal composition with x = 0.44 exhibits electrostrain of ~0.10% at 80 kV cm -1 through irreversible pseudo-cubic to rhombohedral structural transformation followed by ferroelectric domain switching. Unlike BF-ST-Nb systems that maintain pseudo-cubic symmetry, the BF-ST-Mn undergo irreversible phase transitions. Synchrotron XRD reveals initial structural transformation during the first electrical cycle, followed by domain switching in subsequent cycles. It provides promising pathways for lead-free actuator applications requiring high electrostrain at moderate driving fields.
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Jan 2026
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I21-Resonant Inelastic X-ray Scattering (RIXS)
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Open Access
Abstract: Oxygen redox (OR) in Li1.2Ni0.13Co0.13Mn0.54O2 (LRNMC) and Na0.67Mg0.28Mn0.72O2 (NMMO) has been associated with the formation of embedded molecular O2 due to the appearance of their distinctive features in RIXS, while it is unclear whether OR also affects the oxygen left in the lattice. Here we use high-resolution oxygen K-edge resonant inelastic X-ray scattering (RIXS) at threshold excitation (527.5 – 529.5 eV) revealing lattice responses due to OR. We find that both cathodes show pronounced multiphonon progressions, which are either altered or activated upon charging. The first progression, with a fundamental energy loss ∼67-74 meV, matches the A1g lattice-oxygen mode observed by Raman spectroscopy, confirming its bulk origin. The second progression that exhibits a fundamental loss of ∼98 meV appears only at the highest state of charge and is resonant with the new pre-edge states at 527.5 eV. The latter mode emerges concurrently with the characteristic trapped-O2 RIXS signal and is strongly coupled to an occupied electronic band near the Fermi level, indicating that OR may not only contribute to the formation of molecular O2, but also perturbs lattice oxygen states, likely via polaron-forming oxidized lattice oxygen.
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Dec 2025
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Maryia
Zinouyeva
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Martina
Fracchia
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Giulia
Maranini
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Davide
Impelluso
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Nicholas B.
Brookes
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Lorenzo
Grilli
,
Kurt
Kummer
,
Francesco
Rosa
,
Matteo
Aramini
,
Giacomo
Ghiringhelli
,
Paolo
Ghigna
,
Marco
Moretti Sala
,
Mauro
Coduri
Open Access
Abstract: We employ several X-ray based techniques, including X-ray diffraction, X-ray absorption spectroscopy and resonant inelastic X-ray scattering, to disentangle the contributions of individual chemical species to the structural, electronic and magnetic properties of high-entropy oxides. In the benchmark compound Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O and related systems, we unambiguously resolve a sizable Jahn–Teller distortion at the Cu sites, more pronounced in the absence of Ni2+ and Mg2+, suggesting that these ions promote positional order, whereas Cu2+ ions act to destabilize it. Moreover, we detect magnetic excitations and estimate the strength of the interactions between pairs of different magnetic elements. Our results provide valuable insights into the role of various chemical species in shaping the physical properties of high-entropy oxides.
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Nov 2025
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[34632, 31578]
Open Access
Abstract: Biomass conversion involves transforming sustainable feedstocks into valuable intermediates for the chemical industry. A key biomass-derived platform molecule, 5-hydroxymethylfurfural (HMF), can be converted into various intermediates, including 2,5-diformylfuran (DFF), which has several industrial applications due to its versatile chemical reactivity. Herein, Cu loaded MOF-808, with three different Cu loadings, were synthesised and tested as catalysts for the liquid phase selective oxidation of HMF to DFF with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) were performed to assess the speciation of Cu, with the development of a structure model of MOF-808(Cu3). The structural analysis reveals that single square planar Cu(II) sites are located near the Zr6 cluster and are bonded by coordinating to oxygen atoms of capping MeOH and H2O ligands. Amongst the synthesised catalysts, MOF-808(Cu3) exhibited the highest catalytic activity after 12 h, achieving a high HMF conversion (95.5 ± 2.7%) and DFF yield (78.9 ± 1.3%) at 30 °C. The nature of the catalytic reaction is heterogeneous as the yield of DFF decreases after the removal of the solid catalyst. The demonstration of catalytic activity with high selectivity under near ambient conditions advances the application of porous metal–organic framework-based catalysts for selective liquid phase oxidations.
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Oct 2025
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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
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Diamond Proposal Number(s):
[33415, 34976]
Open Access
Abstract: Electro-oxidation is one of the most promising and eco-friendly technologies for water decontamination. However, its industrial application is still limited by the high cost, poor faradaic efficiency, low durability, and potential toxicity of common high-power oxidation anodes. These challenges have been addressed by developing a novel composite comprising a mixed metal oxide (NiMnO3) and reduced graphene oxide (rGO). The NiMnO3–rGO anode allowed the fast and complete removal of phenol. Among different highly porous substrates, graphite felt (GF) led to the highest energy efficiency, since the GF/NiMnO3–rGO anode yielded 100% phenol removal within only 30 min at a current density as low as 10 mA cm−2, which was accompanied by 85% COD removal at 120 min. This anode demonstrated excellent stability, maintaining 100% phenol removal efficiency across five consecutive cycles while also showing low energy consumption (60–65 Wh (kg COD)−1). Operando X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) analysis provided mechanistic insights. It is demonstrated that rGO shifts the ˙OH production pathway towards the lattice oxygen mechanism (LOM), in contrast to the adsorbate evolution mechanism (AEM) observed for NiMnO3 alone. This mechanistic shift supports the enhanced stability and sustained electrocatalytic activity, contributing to the high performance of the GF/NiMnO3–rGO composite anode in the context of a more sustainable technology for treating organic contaminants.
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Oct 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[39034]
Open Access
Abstract: Composite co-ionic ceramic electrolytes that combine proton and oxide ion conductors hold potential for co-electrolysis of CO2 and H2O for syngas production due to flexible control of the transport numbers of the two charge carriers. Contrary to purely oxide ion co-electrolysis, co-ionic co-electrolysis embodies the supply of CO2 and H2O separately to the negative and positive electrodes, respectively. This study focuses on the development of a chemically stable co-ionic composite electrolyte of an acceptor-doped Ba(Zr,Ce)O3 proton conducting perovskite phase and an acceptor-doped (Ce,Zr)O2 oxide ion conducting fluorite phase, annealed at temperatures between 800 and 1600 °C. Comprehensive evaluations of the composites' microstructure, hydration, and conductivity were performed, revealing that annealing temperature and cation selection significantly impact the properties and performance of co-ionic electrolytes. Higher annealing temperatures drive cation redistribution, with the perovskite phase becoming zirconium-rich at its B-site and depleted in acceptor dopants, resulting in diminished hydration and protonic conductivity. Herein, we show that composites pairing cerium-rich fluorite phases (e.g., Ce0.8Gd0.2O1.9, CGO20, or Ce0.8Y0.2O1.9, CYO20) display markedly improved performance. The BaCe0.8Y0.2O2.9 (BCY20)–CYO20 system (1[thin space (1/6-em)]:[thin space (1/6-em)]1 weight ratio) achieved the highest conductivity (σ = 0.01 Scm−1 at 650 °C in wet Ar), establishing itself as a promising candidate for co-ionic electrolyte applications in solid oxide electrochemical cells.
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Sep 2025
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