B18-Core EXAFS
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Open Access
Abstract: Metal nanoparticles are widely considered for heterogeneous catalysis due to their high atomic efficiency and tunable active microenvironment, but their specific functional tendencies are still unclear. Here, we report that a Rh@ZrO2/NC catalyst with only 0.1 wt% Rh exhibits exceptional catalytic performance and high selectivity (p-nitroacetophenone conversion-98.6 %, p-aminoacetophenone selectivity-100 %, r-56.4 molp-nitroacetophenone/(molRh·min)) towards the hydrogenation of the -NO2 group in nitroarene to -NH2. This is because the interaction between Rh species and “ZrO2-N” results in significant hydrogen spillover in the catalyst, as supported by DFT calculations. Extensive characterizations from TG, DTG, NAP-XPS, in-situ Raman spectroscopy, in-situ DRIFT spectroscopy and DFT calculations further confirm the adsorption, activation and dissociation of hydrogen on Rh nanoparticles. The H* species migrate readily over ZrO2-NC, to facilitate the catalytic activity and selectivity for the hydrogenation of nitroarene. This study presents a new approach to develop highly efficient and selective metal nanoparticle-catalysts for cost-effective hydrogenation reactions.
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Dec 2025
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B18-Core EXAFS
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Diamond Proposal Number(s):
[36598]
Open Access
Abstract: O3 phase NiFeMn- based layered transition metal oxides have attracted interest for positive electrode materials for Na-ion batteries. However, they generally suffer from challenges like phase transitions and Fe migration. Recently, the substitution of Ca into the Na layer, serving as a ‘pillar’, has proven to be an effective approach to overcome these challenges. Here, we systematically studied the composition-dependent Ca pillaring effect on the electrochemical performance and structure evolution of two O3 phase NiFeMn-based layered transition metal oxides. It is found that, although moderate Ca doping in high-Ni system - Na1-2xCaxNi0.25Mn0.25Fe0.5O2 (x = 0.00, 0.03) enhances cycling stability and reduces polarization, excessive doping compromises rate capability and does not effectively prevent Fe migration. Conversely, high-Mn system - Na1-2xCaxNi0.17Mn0.33Fe0.5O2 (x = 0.00, 0.04) exhibits a more robust and beneficial response to Ca incorporation, showing enhanced structural integrity, improved redox reversibility, and effective suppression of Fe migration. This study provides insights into the tunable chemical environments of transition metal oxides, thereby advancing the design of high-performance positive electrode materials and contributing to the development of next-generation sodium-ion batteries.
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Dec 2025
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[34311]
Abstract: Rice is a staple food for over half the world's population. This study uniquely investigates the spatial distribution of key micronutrients (Cu, Mn, Fe, Zn) in cooked brown, white, and parboiled rice using Synchrotron Micro-X-ray Fluorescence (sXRF) for the first time. Complementary analysis with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) validates bulk elemental concentrations. Results from this dual-approach study reveal significantly higher micronutrient concentrations in brown rice compared to white or parboiled rice, with nutrients predominantly localised in the peripheral layers and minimal presence in the endosperm. Notably, sXRF imaging identified nutrient-rich pockets within the grain periphery, offering new perspectives on nutrient distribution beyond peripheral accumulation. Additional insights include the impact of rice section thickness (50 and 150 μm) and beam dwell times (0.5 and 30s) on sXRF sensitivity and resolution, highlighting trade-offs in detection capabilities, advancing our understanding of micronutrient localisation in cooked rice.
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Dec 2025
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[35875]
Open Access
Abstract: Aqueous zinc metal batteries (AZMBs) face significant challenges in achieving reversibility and cycling stability, primarily due to hydrogen evolution reactions (HER) and zinc dendrite growth. In this study, by employing carefully designed cells that approximate the structural characteristics of practical batteries, we revisit this widely held view through in-operando X-ray radiography to examine zinc dendrite formation and HER under near-practical operating conditions. While conventional understanding emphasizes the severity of these processes, our findings suggest that zinc dendrites and HER are noticeably less pronounced in dense, real-operation configurations compared to modified cells, possibly due to a more uniform electric field and the suppression of triple-phase boundaries. This study indicates that other components, such as degradation at the cathode current collector interface and configuration mismatches within the full cell, may also represent important barriers to the practical application of AZMBs, particularly during the early stages of electrodeposition.
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Dec 2025
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B18-Core EXAFS
I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[33674, 35117, 35776, 40942]
Open Access
Abstract: Metal–organic frameworks (MOFs) are entering water technologies on the premise that abiotic stability predicts ecological safety. We overturn this assumption by showing that UiO-66 – often regarded as chemically and structurally robust – remains intact after 7-day aging in natural borehole water yet undergoes rapid in vivo transformation in Daphnia magna. Synchrotron Microfocus X-ray absorption spectroscopy (XAS) revealed collapse of the ordered Zr–carboxylate coordination into disordered Zr–O environments within the gut; Extended X-ray Absorption Fine Structure (EXAFS) showed loss of second-shell features, and Transmission Electron Microscopy (TEM) confirmed loss of crystallinity with nanoscale aggregates appearing within 24 h of ingestion. Although acute immobilization was limited (48 h EC50 ≈ 26.5 μg mL–1), a sublethal, environmentally relevant exposure (10 μg mL–1) caused pronounced chronic effects: brood initiation was delayed by 3–5 days and cumulative reproduction decreased by ∼74% without mortality. We attribute these outcomes to gut-level transformation and associated energetic/physiological burdens, not captured by standard acute tests. These results show that abiotic stability does not necessarily imply biological inertness and highlight the need to integrate in vivo transformation pathways with chronic end points in environmental risk assessment for water-sector materials. This perspective provides a mechanistic basis to inform Safe-and-Sustainable-by-Design (SSbD) MOFs before widespread deployment in water treatment.
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Dec 2025
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Hui
Sun
,
Yanan
Jiang
,
Miaolin
Lan
,
Ming
Zhou
,
Gangshun
Yi
,
Juan
Shen
,
Tingting
Deng
,
Liqin
Liu
,
Yang
Huang
,
Yu
Li
,
Jinfu
Su
,
Yanling
Lin
,
Zhenqin
Chen
,
Lizhi
Zhou
,
Tingting
Li
,
Hai
Yu
,
Tong
Cheng
,
Yali
Zhang
,
Lunzhi
Yuan
,
Shaowei
Li
,
Ying
Gu
,
Peijun
Zhang
,
Ningshao
Xia
,
Qingbing
Zheng
Open Access
Abstract: The rapid evolution of SARS-CoV-2 and the subsequent emergence of Omicron subvariants pose significant challenges to the efficacy of existing vaccines and therapeutics, including those previously reported most broad neutralizing antibodies (bnAbs). Here, we investigated the molecular basis of the altered neutralization profile of a bnAb, 1C4, against recent variants. 1C4 is effective against early variants from Alpha to Omicron BQ.1, but is circumvented by BQ.1.1, XBB and thereafter variants, primarily due to an additional R346T mutation that diminishes its binding affinity. Cryo-electron microscopy analysis revealed that despite the loss of neutralizing potency, 1C4 retained residual binding to the spike protein of immune-evasive variants such as XBB, which harbor altered receptor-binding domain (RBD). Furthermore, 1C4 exhibited a diminished capacity to inhibit ACE2 engagement with Omicron variants, amplifying the intricacies of viral immune evasion tactics. To address this, we employed the mi3-SpyCatcher-based nanoparticle to polymerize 1C4 (mi3-1C4), which reestablished the neutralization potency against recent variants by enhancing avidity via multivalent binding. Such multivalent binding can promote efficient spike aggregation as well as viral cross-linking, thereby providing enhanced protection against both the infection of Beta and XBB variants in a hamster model. Together, our findings delineate the molecular landscape of immune evasion by neutralizing antibodies and provide strategic insight for the adaptation of antibody engineering to keep pace with viral evolution.
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Dec 2025
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[33430]
Open Access
Abstract: The electrochemical reduction of N2 in aqueous media and ambient conditions would present a great advancement in the defossilization of the fertilizer and energy sector, if the obstacles to this technology were not as significant as they are at present. Some recent reports have raised doubts about whether the electrochemical nitrogen reduction reaction (eNRR) is even possible in aqueous media. Herein, a type of metal-organic framework (MOF)-derived Fe and Zn single atom catalyst for the eNRR is revisited, which has been reported more than once in recent literature to be active for eNRR in aqueous media. Electrochemical measurements reported here show the inactivity of the investigated iron-based catalysts for the eNRR in neutral aqueous media when contaminations are excluded. In stark contrast, the reduction of NOx contamination to ammonia is shown to be a possible reason for false positive results. The reduction of nitrate to ammonia (NO3-RR) is itself an emerging field of research that investigates the conversion of nitrate from wastewater to ammonia. For the NO3-RR, the MOF-derived catalysts show good activity and selectivity, which depends on the iron site density in the catalyst. An ammonia yield of 19.1 mg h−1 mgcat−1 at −1.0 V versus RHE and a maximum faradaic efficiency (FE) of 100% at −0.9 V versus RHE is achieved.
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Dec 2025
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Abstract: The low-temperature performance of mixed-composition perovskite solar cells (PSCs) reflects the complex interplay among thermal effects, bandgap renormalization, and structural phase behavior. Temperature-dependent structural, optical, and electrical measurements reveal a maximum power conversion efficiency at 263 K, which coincides with the onset of the cubic-tetragonal phase coexistence. At this temperature, symmetry lowering is observed, accompanied by a split emission band and increased current–voltage hysteresis, consistent with structural heterogeneity. Device simulations show that any benefit from mixed-phase band alignment is conditional on effective interphase passivation. Consequently, the mixed phase is best described as a loss-minimum condition at well-passivated cubic–tetragonal interphases with stable collection. Our findings identify a narrow mixed-phase window in which phase coexistence couples to the optoelectronic response and enhances the device performance, providing fundamental insight into temperature-dependent structure–property relations in hybrid perovskites.
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Dec 2025
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B18-Core EXAFS
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Diamond Proposal Number(s):
[34632]
Abstract: Electrocatalytic CO2 reduction (ECO2R) to high-value chemicals is a promising method to upcycle emitted CO2, but it is also a fascinating scientific challenge. Catalyst materials, as well as cell configurations, play a pivotal role in the efficacy and efficiency of the ECO2R reaction, which also dictates reaction pathways and product selectivity. In this work, we employ the isotopological Zr- and Ce-based UiO-67 metal–organic frameworks (MOFs) that contain Pd species in a zero-gap gas diffusion cathode electrode configuration, where the water content, i.e., relative humidity (RH) level, in the CO2 gas stream can be varied. We show that only UiO-67-based MOFs containing Pd embedded in their pores can produce syngas, while the product selectivity can be controlled by varying the RH levels in the gas stream. The pristine MOFs (precatalysts) undergo chemical and structural transformation during the ECO2R reaction, forming the active catalysts toward CO2 electroreduction to syngas. Our work highlights the effect of water content on the selectivity during ECO2R, but also the need for predictive catalyst design for effective electroreduction of CO2 to high-value chemicals.
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Dec 2025
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DIAD-Dual Imaging and Diffraction Beamline
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Loris
Chavée
,
Emile
Haye
,
Jochen M.
Schneider
,
Stanislav
Mráz
,
Andreas
Pflug
,
Dennis
Barton
,
Armel
Descamps
,
Claudie
Josse
,
Jérôme
Müller
,
Pavel
Moskovkin
,
James
Marrow
,
Amael
Caillard
,
Stephane
Lucas
Diamond Proposal Number(s):
[34010]
Abstract: The deposition of functional coatings on open-cell foam substrates using magnetron
sputtering is gaining popularity, particularly for applications like Oxygen Evolution
Reaction (OER)/Hydrogen Evolution Reaction (HER) catalysis, batteries, and
supercapacitors. While most research focuses on performance, little attention has
been paid to the coating growth mechanisms or properties within the foam, which could
significantly impact device performance. This work investigates the properties and
growth mechanisms of TiO₂ coatings inside porous foams, using experimental and
modeling techniques.
The structure, composition and thickness of the coating on the outermost surface of
the foam are studied using Focused Ion Beam (FIB), Scanning Transmission Electron
Microscopy (STEM), Energy-Dispersive X-Ray Spectroscopy (EDS), Selected Area
Electron Diffraction (SAED) and High-Resolution Transmission Electron Microscopy
(HRTEM). The experimental results reveal the formation of a dense, (quasi-
)stoichiometric and crystalline coating.
Numerical simulations and experiments highlight the transport of plasma particles in
the foam. Interestingly, Direct Simulation Monte Carlo (DSMC)/Particle-In-Cell Monte
Carlo (PICMC) models, coupled with Mass-Energy Analyzer (MEA) experiments,
demonstrate that the particle flux is reduced, but the particle energy distribution is not
Accepted Manuscript affected while traveling inside the foam. Using kinetic Monte Carlo (kMC) thin film
growth models provided by Virtual CoaterTM, the physical properties of the coating
inside the foam have been modeled, and the drop in coating thickness as well as the
impact of bias voltage on densification, resistivity, and optical absorption are
confirmed. Synchrotron X-Ray Diffraction (SXRD) analyses of the foam demonstrate
that the same crystalline phase is obtained along the foam thickness, but it can be
tailored with bias voltages. The decrease in the recorded SXRD signal with increasing
depth inside the foam also suggests a drop in coating thickness.
The new insights on the properties of coatings inside open-cell foams presented in this
study can be used to improve future foam-based devices.
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Dec 2025
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