I20-Scanning-X-ray spectroscopy (XAS/XES)
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Filip J. R.
Meysman
,
Bent
Smets
,
Silvia
Hidalgo-Martinez
,
Nathalie
Claes
,
Bob C.
Schroeder
,
Jeanine S.
Geelhoed
,
Yun
Liu
,
Jiji
Alingapoyil Choyikutty
,
Tamazouzt
Chennit
,
Thijs
Bodson
,
Alberto
Collauto
,
Maxie M.
Roessler
,
Dmitry
Karpov
,
Sylvain
Bohic
,
Matteo
Aramini
,
Shusaku
Hayama
,
Maxwell
Wetherington
,
Martijn A.
Zwijnenburg
,
Galina
Pankratova
,
Isabel
Pintelon
,
Jean-Pierre
Timmermans
,
Gert
Nuyts
,
Karolien
De Wael
,
Sara
Bals
,
Jo
Verbeeck
,
Han
Remaut
,
Henricus T. S.
Boschker
Diamond Proposal Number(s):
[31284, 36538, 38275]
Open Access
Abstract: Biobased electronics aims for disruptive innovation in sustainable electronics but is obstructed by the low intrinsic conductivity of biomaterials. Recently, fibres were discovered within the cell envelope of multi-cellular cable bacteria, which display an exceptional conductivity for a biomaterial. Yet, the molecular structure and electron transport mechanism remain unresolved, thus precluding a detailed structure-function understanding and the development of biomimetic analogues. Here, we demonstrate that each fibre embeds an extended nickel-organic framework, which consists of a bundle of intertwined nanoribbons, each built from stacked repeat units in which multiple nickel centres are linked by organic dithiolene ligands. This metal-organic supramolecular architecture provides extensive conjugation and electron delocalization, thus enabling exceptional conductance over macroscale distances. This suggests a novel design principle for bio-based electronic materials and opens possibilities for biosynthesis of metal-organic frameworks.
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Sep 2026
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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
E01-JEM ARM 200CF
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Yanqi
Dai
,
Zhangyi
Yao
,
Hao-Xin
Liu
,
Lu
Chen
,
Xinlian
Su
,
Matteo
D'Andria
,
Matthijs A.
Van Spronsen
,
Nitya
Ramanan
,
Shusaku
Hayama
,
Andreas T.
Güntner
,
Chun-Jiang
Jia
,
Feng Ryan
Wang
Diamond Proposal Number(s):
[33314, 33267, 38085, 37962]
Open Access
Abstract: Efficient nitrous oxide (N2O) decomposition relies on coupled redox cycles, yet it remains unclear how deeply into the catalyst these redox changes extend under working conditions and what oxygen-exchange depth is required to sustain turnover. Here we combine inverse CeO2/CuO architectures with depth-resolved X-ray spectroscopy to identify the active redox motif and the operative oxygen-exchange zone. 20 wt % CuO/CeO2 and inverse CeO2/90 wt % CuO catalysts were prepared by flame spray pyrolysis (FSP) and coprecipitation (CP), generating distinct Cu–Ce interfacial structures for N2O conversion. The inverse 90FSP is more active than the conventional 20FSP and coprecipitated 90CP catalysts under the conditions studied. Bulk-sensitive Cu K-edge HERFD-XANES reveals only minor changes in Cu oxidation state under reaction conditions, showing that bulk-averaged Cu redox is not the descriptor for the activity trend. In contrast, surface-sensitive Cu L-edge spectra uncover pronounced, reversible Cu2+/Cu+ cycling that is strongly localized in the surface and subsurface regions and, critically, a sustained surface-subsurface Cu2+/Cu+ redox gradient that is unique to the most active 90FSP catalyst. Mechanistically, this pronounced surface-subsurface Cu2+/Cu+ ratio contrast indicates that N2O-driven surface Cu redox turnover is sufficiently fast that it cannot be fully equilibrated by lattice oxygen exchange (O2– equilibration) with the subsurface. These results identify interface density and temperature-dependent redox depth as a design and diagnostic principle for metal–oxide redox catalysis.
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Aug 2026
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Abstract: We present the first experimental observation of long-unresolved many-body satellite features within the Kα1,2 X-ray emission spectra of zinc (Zn) with statistical significance exceeding 50 σse per data point. These novel structures, “Hidden Satellites”, were discovered using an extended-range high-energy-resolution fluorescence detection (XR-HERFD) technique at the I20-Scanning beamline of the Diamond Light Source in UK. The measurements employed a 14-crystal analyzer array specifically designed to enhance both energy resolution and statistical accuracy. The Hidden Satellites are revealed within the main Kα1,2 emission peak and exhibit a systematic evolution with increasing incident photon energy. Principal component analysis (PCA) was employed to independently isolate these novel features and trace the evolution of these structures. Remarkably, these hidden features contribute 15% to 20% of the total emission intensity, directly challenging the long-standing assumption that the many-body reduction factor (S
2
0
) is constant. We observe that S
2
0
exhibits a clear energy dependence, changing by over 20% over the observed energy range, with broad implications for the analysis and interpretation of X-ray absorption and emission spectra in transition metals and their compounds. Overall, it provides a new foundation for interpreting X-ray spectroscopy, influencing thousands of studies across chemistry, physics, and biology. Despite zinc metal being considered a “simple” d10 metal, the complexity of structure, asymmetry and evolution of these new processes is dramatic and points to a rich new area of inquiry.
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Aug 2026
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[39324]
Open Access
Abstract: Fertilizers derived from ammonia (NH3) play a vital role in global food production, and ammonia is also emerging as a carbon-free fuel or hydrogen carrier. To facilitate the use of ammonia as an energy carrier, there is a need to develop catalysts that enable ammonia production under milder conditions than the current Haber–Bosch process. Industrially, high temperatures and pressures (>450 °C, >100 bar) are required, partly due to the need to operate at conditions where the iron oxide (Fe2O3) catalysts are reduced to the active Fe phase. Herein, we show that intimate contact between Fe2O3 nanoclusters and alkali metal hydrides (LiH, NaH, and KH), arising from their co-confinement in nanoporous carbon, leads to high ammonia production under mild conditions (∼250 °C and 10 bar), without prior reduction of the Fe2O3. The alkali metal hydrides show profound differences in catalytic activity due to the differences in their interaction/reactivity with Fe2O3 nanoparticles, as well as activation of N2. These results show that co-nanoconfinement of metal hydrides and transition metal oxides is a promising approach toward developing catalysts for low-temperature ammonia synthesis.
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Jul 2026
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[39257]
Open Access
Abstract: We discover satellites in Zn at emission energies of 8670–8675 eV. The satellite is detected with a significance exceeding 51.6 per pixel, enabled by the exceptional signal-to-noise ratio of the new dataset and novel technique. We have created the eXtended-range high-energy-resolution fluorescence detection (XR-HERFD) technique and applied it to Zn (Z = 30) using a novel 14-crystal analyser spectrometer. For this current work, data collection developed the first DOSE-S collection macros for Discovery-Onset-Spectrometry-Evolution of new Satellite processes. The energy dependence of the discovered satellite is tracked from the onset of the process at approximately 10791.7 eV through its evolution to higher energies. The satellite exhibits a clear manifold structure, consistent with multiple shake-off processes. We develop and apply Principal Component Analysis (PCA) and independently isolate the manifold of the satellite and prove the incident-energy evolution. We also fit the evolution to theoretical quantum mechanical models of such processes to provide strong confirmation of the physical origin. These findings demonstrate XR-HERFD’s capability to resolve weak many-body features and suggest new opportunities for studying shake processes and the many-body reduction factor . By resolving these satellites in what many people believed was a nominally simple metal and revealing rich many-body behaviour, this work opens a pathway to a physically grounded understanding of many-body effects in X-ray spectroscopy.
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Jul 2026
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Open Access
Abstract: We report the technical design, implementation and operation of a newly developed X-ray emission spectrometer on the I20 beamline at Diamond Light Source. The spectrometer consists of 14 crystal analysers arranged in an up–down configuration, allowing for operation in one- or two-colour acquisition modes. Since beginning operations in 2023, the spectrometer has substantially enhanced the capability of the beamline to perform X-ray emission spectroscopy (XES) and has demonstrated high reliability with minimal operational issues during user experiments. The latter achievement is particularly significant given the complexity of the instrument, and the difficulty of maintaining the Rowland condition when scanning the energy. We show that the spectrometer can effectively measure spectra in two-colour mode and is capable of detecting weak valence-to-core emission features with a significantly improved signal-to-background ratio. We also present data taken using a newly developed quick-scanning XES acquisition mode, which enables data collection in seconds rather than minutes. This mode opens up possibilities for time-resolved studies and investigating radiation-sensitive materials.
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May 2026
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B18-Core EXAFS
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[21659, 28356]
Open Access
Abstract: Understanding the interplay between redox behavior and structural stability is crucial for the development of transition metal oxides in electrocatalysis. In this work, we use both X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) to investigate the electrochemical response of Mn-based perovskite oxides (La1–xCaxMnO3) under oxygen reduction reaction (ORR) conditions. This dual approach enables tracking of changes in both the oxidation state and local coordination environment. Mn Kβ XES data show that oxidation-state changes are reversible, despite a shift in transition potentials across a range of compositions, including CaMnO3. In contrast, Mn K-edge EXAFS analyses reveal that while LaMnO3 retains structural integrity, CaMnO3 undergoes irreversible structural changes at low potentials, associated with the collapse of the perovskite framework. Intermediate compositions show partially reversible structural behavior. This decoupling of redox reversibility and structural instability, a picture only accessible through the use of XAS and XES, provides critical insight into the complex behavior of these materials under operational conditions. Additionally, our analysis shows that Mn(II) formation is only detected in CaMnO3 at potentials more negative than 0.4 V (vs RHE). The ORR onset is associated with Mn(IV) reduction, while peroxide formation correlates with an increased Mn(III)/Mn(IV) ratio, supporting a 2e– + 2e– reduction pathway. This study demonstrates the power of XAS and XES analyses to disentangle electronic and structural dynamics, providing a more complete understanding of activity–stability relationships in perovskite electrocatalysts.
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Apr 2026
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B18-Core EXAFS
I20-Scanning-X-ray spectroscopy (XAS/XES)
|
Jarrod C.
Lewis
,
Joseph
Fihosy
,
Akhil
Gupta
,
James
Tufnail
,
Kirk
Adams
,
Matthew
Coulson
,
Petr
Zagura
,
William
Iliffe
,
Nianhua
Peng
,
Diego
Gianolio
,
Shusaku
Hayama
,
Rebecca J.
Nicholls
,
Sofia
Diaz-Moreno
,
Susannah C.
Speller
Diamond Proposal Number(s):
[33243]
Open Access
Abstract: Understanding how irradiation degrades superconductivity in REBCO coated conductor is a pressing field of research for the development of compact fusion devices. Here, defect formation in GdBa2Cu3O
coated conductor is studied using a high dose of 2 MeV He
ion irradiation. While laboratory based X-ray diffraction and magnetometry measurements show that the crystal structure becomes less well ordered with the loss of superconductivity in the material, transmission electron microscopy reveals a complex landscape of structural defects within the as-manufactured tape which complicate the identification and characterisation of irradiation induced structural changes. To resolve this, three sets of polarisation dependent extended X-ray absorption fine structure (EXAFS) spectroscopy experiments were carried out to map the local structure of the Gd, Ba, and Cu atomic sites within the material, providing three independent probes for studying irradiation defects within the structurally anisotropic REBCO unit cell. Here the Ba and Cu environments were the more sensitive to the irradiation treatment, with only small changes to the Gd local structure observed. Both the Ba and Cu local structures retained much of the pristine structure in the a/b-plane following irradiation, with greater shifts evident in the c-axis aligned measurements. In the irradiated Cu K edge EXAFS analysis, a shifted peak in the c-axis aligned measurements is observed that is not compatible with the REBCO local structure. This is attributed to an O site irradiation defect motif consistent with a Frenkel defect.
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Apr 2026
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Yuvraj
Vaishnav
,
Mohamad
Abou-Daher
,
Cristina I. Q.
Silva
,
Rohit K.
Rai
,
Walid
Al Maksoud
,
Marcell
Toth
,
Mohandoss
Viswanathan
,
Peng
Ren
,
Fumitaka
Takeiri
,
Shusaku
Hayama
,
Samy
Ould-Chikh
,
Mohamed Nejib
Hedhili
,
Maxim
Avdeev
,
Wen
Yin
,
Saburo
Hosokawa
,
Genki
Kobayashi
,
Isaac
Abrahams
,
Aamir
Farooq
,
Javier
Ruiz-Martinez
,
Yoji
Kobayashi
Diamond Proposal Number(s):
[31497]
Open Access
Abstract: High-entropy oxides are attracting attention for catalysis, but there are relatively few detailed studies on their precise structure, hampering true detailed studies on fundamental properties affecting their activities. In addition, diffusion has been often characterized as generally slow in high-entropy systems. Here, we determine the precise oxygen content and structure of the fluorite-like high-entropy oxide (La, Ce, Pr, Nd, Y)O1.68 and have identified a large oxygen storage capacity based on efficient Ce/Pr redox due to facile oxide diffusion pathways and suppression of sintering. The structure and composition were identified through a combined Rietveld refinement of X-ray and neutron diffraction data, and the oxidation state of Ce and Pr was investigated by high energy resolution fluorescence detected–X-ray absorption near edge spectra (HERFD–XANES). (La, Ce, Pr, Nd, Y)O1.68 utilizes the full redox range of Ce/Pr, resulting in a high oxygen storage cumulative capacity despite the lower content of Ce/Pr compared to other well-known ceria derivatives. Diffusion pathway analysis by bond valence site energy mapping shows decreased barriers for oxide anion diffusion through the bulk, also benefiting redox reactions. The high-entropy nature also suppresses sintering, resulting in better cycling performance. This results in a higher performance as a methane oxidation catalyst support. We also investigate its use as a NOx reduction catalyst support.
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Mar 2026
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[31906, 39961]
Open Access
Abstract: Mercury (Hg) is a global environmental concern due to its microbial conversion to methylmercury (MeHg), a potent neurotoxin that bioaccumulates in food webs and poses risks to ecosystems and human health. Thiol functional groups (RSH) play an important role in controlling Hg(II) speciation and bio-uptake in methylating bacteria, yet the spatial distribution and density of these thiols within cells remain largely unknown. We isolated subcellular fractions of the Hg methylating bacterium Geobacter sulfurreducens in the exponential growth phase, and used Hg LIII-edge EXAFS (Extended X-ray Absorption Fine Structure) to quantify thiols in the extracellular medium, inner and outer membranes, periplasm and cytoplasm. The whole-cell thiol content was determined to be 1.3 × 10−10 μmol cell−1. The inner membrane contributed 7.1 × 10−11 (53%), the outer membrane 1.2 × 10−11 (9%), the periplasm 3.6 × 10−11 (27%) and the cytoplasm 1.5 × 10−11 μmol cell−1 (11%). The extracellular fraction contributed an additional 5.7 × 10−11 μmol cell−1, corresponding to 30% of the thiols of the cell culture. Local thiol density (thiols normalized to TOC in individual compartment, RSH/TOC, μmol g−1 C) was 36, 450, 140, 600 and 29 μmol g−1 C in the cytoplasm, inner membrane, periplasm, outer membrane and extracellular fractions, respectively. EXAFS analyses demonstrate Hg-thiolate coordination across all compartments, with Hg-O/N bonding and elemental Hg0 formed at higher Hg loadings. In the periplasm, Hg-disulfide and traces of β-HgS were detected. The high thiol density at the membranes, relative to other compartments, may imply they have an important role in the retention and internalization of Hg(II). Periplasmic thiols may modulate Hg(II) transfer between membranes, and cytoplasmic thiols may regulate the intracellular availability of Hg(II) for methylation. This work provides the first compartment-resolved quantification of thiol abundances and densities in a model Hg-methylating bacterium at subcellular level, offering a mechanistic framework for understanding the speciation, bioavailability, and subcellular transformation of Hg(II) with relevance for other soft metals (e.g., Cd, Pb, Zn, Ag, and Cu).
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Feb 2026
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