B18-Core EXAFS
|
Diamond Proposal Number(s):
[30629]
Abstract: Geopolymer cements are highly promising materials for long-term immobilisation of Strontium-90 radioactive waste, offering superior durability and cation binding sites compared to conventional Portland cement matrices. This study investigates the influence of prolonged leaching on the Sr immobilisation mechanism and structural integrity of metakaolin-based geopolymers using the ANSI/ANS 16.1 semi-dynamic leaching test. All geopolymers demonstrated high Sr retention, with Leachability Indices at least 14.7 for all samples, significantly exceeding the industry guideline of 6.0, confirming their effectiveness. Importantly, potassium silicate–activated geopolymers exhibited reduced Sr release and substantially lower leaching rates than sodium silicate–activated geopolymers. Multiscale spectroscopic and diffractometric analysis, including synchrotron X-ray absorption spectroscopy and multinuclear high-field solid-state MAS NMR probing 39K, 23Na, 27Al, and 29Si, revealed that the alkali aluminosilicate gel framework remained structurally stable after leaching for 28 days, with no significant alterations to Si and Al bonding environments. Sr release is primarily controlled by diffusion, and the dominant immobilisation mechanism is the formation of insoluble SrCO3. Atomic-level Sr structural analysis using XANES/EXAFS revealed an increase in the average Sr coordination number in both systems after leaching, with a more pronounced rise in potassium-based geopolymers, consistent with enhanced SrCO3 formation. Overall, these findings demonstrate that geopolymers maintain structural integrity during leaching and show for the first time that using potassium rather than sodium as an alkali activator is definitively more advantageous for maximising the long-term effectiveness of geopolymer wasteforms. This demonstrates their strong suitability as wasteforms for the safe long-term immobilisation of Sr-containing radioactive wastes.
|
Jul 2026
|
|
Krios I-Titan Krios I at Diamond
|
Diamond Proposal Number(s):
[37221]
Open Access
Abstract: Biocatalytic cascades offer a promising route for CO2-fixation into valuable chemicals, addressing the urgent need for efficient, sustainable technologies to reduce CO2 emissions. This paper describes an enzymatic route converting gaseous CO2 and acetaldehyde into enantiopure lactic acid, widely used in diverse industries. A newly characterized pyruvate decarboxylase from Neoasia chiangmaiensis (NcPDC) enabled acetaldehyde carboxylation to pyruvate. To suppress the competing carboligation to acetoin, acetaldehyde was reversibly trapped with Tris. Pyruvate was reduced to lactate by lactate dehydrogenase, coupled with glucose dehydrogenase for NADH regeneration via D-glucose oxidation to D-gluconic acid. Up to 65% lactate yield was achieved. Repeated acetaldehyde dosing resulted in a 27 mM titer, representing a >100-fold improvement over previous reports. At 0.5 L scale, using a gas mixture mimicking industrial-grade CO2, we obtained 21 mM D-(–)-lactic acid, 42% yield and >98% e.e., demonstrating scalability and robustness. Finally, replacing the D-(–)-selective lactate dehydrogenase with an L-(+)-selective variant at small scale enabled production of L-(+)-lactic acid at 41% yield and >93% e.e, allowing switchable access to either enantiomer. A volumetric productivity of 1.1 × 10−2 g L−1 h−1 ranks among the most efficient minimal enzymatic routes developed to date for CO2-to-lactate conversion.
|
Jun 2026
|
|
|
|
Open Access
Abstract: The global transition from a coal-based energy economy to a green hydrogen economy, together with the demand for energy utilization efficiency, has intensified interest in ammonia as a carbon-free hydrogen energy carrier which is capable of storing and transporting renewable energy at scale. Efficient regeneration of hydrogen through thermal ammonia decomposition, enabled by advanced downstream technologies such as membrane reactors and purification systems, offers a techno-economically mature and evolving pathway. However, achieving low-temperature, energy-efficient ammonia decomposition remains a fundamental challenge. At the heart of this challenge lies the rational design of heterogeneous thermocatalysts capable of overcoming intrinsic kinetic limitations. Through critical examination of the vast research on catalyst systems and activity studies, we identify that tailored metal-support systems often give rise to multiple reaction pathways that govern the overall kinetics. To scientifically elucidate the origins of enhanced catalytic performance, the precise understandings on the nature of active sites and their coordination environments is the core. This requires precise identification of catalytically relevant sites, rigorous correlation between structure and reactivity, and operando-level insights into dynamic phase evolution. In this review, we reframe ammonia decomposition catalysis through the lens of active-phase chemistry. Based on our current understanding of active centres across different catalyst categories, we highlight strategies for rational catalyst design grounded in active phases and coordination environment. We further discuss advanced characterization methodologies capable of tracking active sites and unravelling their specific mechanistic contributions.
|
Jun 2026
|
|
I07-Surface & interface diffraction
|
Olivia
Gough
,
Katherine
Trinkaus
,
Pascal
Kaienburg
,
Zhenlong
Li
,
Andrea E.
Lauritzen
,
Jonathan
Rawle
,
Hugo
Norris
,
James
Hilfiker
,
Joel
Smith
,
Alessandro
Veneri
,
Gregory
Su
,
Moritz
Riede
Diamond Proposal Number(s):
[30773, 32922]
Abstract: The microstructure of organic small molecule (SM) layers in organic solar cells (OSCs) strongly influences device performance by impacting light absorption, charge transport, and recombination. We demonstrate that ellagic acid (EA), a naturally derived templating layer, induces substantial morphological and thus optoelectronic changes in the vacuum thermally evaporated (VTE) donor molecule DCV5T-Me(3,3). Using in situ grazing incidence wide-angle X-ray scattering (GIWAXS) during thin film deposition in the purpose-built MINERVA VTE chamber at Diamond Light Source, we show that a 5 nm EA layer reorients DCV5T-Me from an edge-on to a face-on molecular packing motif. This templating effect persists for up to around 90 nm of film thickness.
Through UV-vis spectrophotometry and photoluminescence (PL) spectroscopy, we observe a shift towards H-aggregation and decreased light absorption in the donor molecule with the EA template. Atomic force microscopy (AFM) shows that the donor morphology changes as a function of thickness from the donor-templating interface. In DCV5T-Me(3,3):C60 bulk heterojunction devices, the EA layer helps retain donor crystallinity and enhances short circuit current (J
), despite the lower absorption. Maximum power conversion efficiency in our devices is achieved with a 5 nm templating layer, which provides sufficient structural templating while maintaining partial interfacial contact for efficient charge extraction. We hypothesise that the improvement in J
is likely driven by enhanced charge carrier dynamics due to the orientation change, shift toward H-aggregation, and change in growth mode.
|
Jun 2026
|
|
I18-Microfocus Spectroscopy
|
Diamond Proposal Number(s):
[36021]
Open Access
Abstract: Sulfur isotopes in mantle plume-derived magmas show heterogeneities attributed to recycling of material from the Earth's surface. The sedimentary sulfur isotope record exhibits dramatic temporal variations over Earth history, raising the question of whether its secular evolution is echoed in mantle plume-derived magmas. We present new secondary ion mass spectrometry and X-ray absorption near-edge structure measurements of δ34S and Fe3+/ΣFe in naturally glassy melt inclusions from the 2.7 Ga Belingwe komatiites. We find that δ34S of Belingwe melt inclusions is relatively homogeneous (+3.2 ± 0.9) and elevated relative to the depleted upper mantle. We evaluate explanations for elevated magmatic δ34S including degassing, sulfide fractionation, assimilation, subduction-like processes, and mantle recycling. We find no evidence for significant sulfur isotope fractionation via degassing or sulfide saturation. The elevated δ34S in the Belingwe komatiites could reflect late-stage assimilation of sediments or seawater. Alternatively, Belingwe komatiites may have formed in a subduction-like setting, as modern arcs display a bias toward positive δ34S. However, we find these scenarios less favorable. Instead, our preferred interpretation is that elevated δ34S was supplied to the komatiite mantle source via recycled lithologies such as sediments, altered oceanic crust, and/or pyroxenite. Combined with δ34S data from mantle plume-derived magmas spanning a wide age range, our results resemble the secular evolution of δ34S in surface reservoirs. We suggest that the δ34S record in mantle plume-derived magmas may echo secular evolution in the surficial sulfur reservoir with a delay of several hundred million years, linking Earth's surface and interior sulfur cycles.
|
May 2026
|
|
B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
|
Sherif
Hefney
,
Seth
Koloski
,
Phillip
Elias
,
Damilola Tomi
Awotoye
,
Mohamed
Ammar
,
Hannah
Folarin
,
Lihua
Zhang
,
Matthijs A.
Van Spronsen
,
Christie M.
Sayes
,
Alexander
Laskin
,
Jonas
Baltrusaitis
Diamond Proposal Number(s):
[40617]
Open Access
Abstract: Wastewater-derived struvite (MgNH 4 PO 4 •6H 2 O) microcrystals could replace a significant fraction of traditional nitrogen and phosphorus fertilizers, supporting nutrient recycling and sustainability while mitigating environmental impacts such as water eutrophication and atmospheric pollution. However, phosphorus recovery is often hindered by iron interference, as Fe can strongly bind phosphate to form insoluble iron phosphate minerals, such as vivianite, through pH-, redox-, and organic-matter-dependent processes. These Fe-containing anthropogenic solids represent an unexplored source of anthropogenic iron flux into the environment. This study investigates the influence of Fe concentration on struvite formation from wastewater using magnesium carbonate (MgCO 3 ) as a naturally abundant Mg source in simulated wastewater containing up to 500 ppm of Fe 3+ . Iron-containing struvite (Fe-struvite) microcrystals were successfully produced and characterized using complementary structural and spectroscopic techniques. Up to 150 ppm Fe 3+ precursor concentration yielded well-defined crystalline Fe-struvite, whereas higher levels resulted in amorphous phases. Low Fe 3+ levels (up to 10 ppm) caused a lattice contraction in struvite due to limited magnesium substitution. Raman micro-spectroscopy revealed that low Fe 3+ concentrations (<10 ppm) allowed coexistence of hydromagnesite (Mg 5 (CO 3 ) 4 (OH) 2 •4H 2 O) with struvite, whereas at >150 ppm Fe 3+, only amorphous phosphate was present. Ion chromatography showed equilibrium aqueous phosphate (PO 4 3-) concentrations decreasing from 235 ppm to 38 ppm with increasing Fe 3+ , while ammonium removal from solution was inhibited. X-ray fluorescence analysis indicated that at >150 ppm Fe 3+ , an iron-rich amorphous phase with Fe:P ≈ 1:1.75 was produced. The findings indicate that recovered Fe-struvite can serve as an anthropogenic iron source to the environment.
|
May 2026
|
|
I18-Microfocus Spectroscopy
|
Diamond Proposal Number(s):
[41814]
Open Access
Abstract: De-icing road salts are widely employed for snow and ice mitigation in cold climate regions, with sodium chloride (NaCl) being the most commonly used salt. The extensive application of NaCl has raised significant infrastructure, sustainability, and environmental concerns, and it has led to the emergence of various alternative de-icing salts, including other chloride-based and organic salts and compounds. In this study, the effect of zinc and acetate species on the corrosion behaviour of steels was systematically investigated using a combination of atmospheric corrosion testing, immersion testing, electrochemical measurements, cross-sectional microscopy, Zn K-edge X-ray absorption spectroscopy (XANES), and thermodynamic speciation modelling. The effect of eight chloride and non-chloride salts and their mixtures on the corrosion of structurally important galvanized steel, mild steel, and high-strength steel was studied. The chloride-based salts were found to be more detrimental than the organic salts to the corrosion of mild and high-strength steels, but all the salts were similarly corrosive to galvanized steel. It was found that the presence of both zinc and acetate species significantly enhanced corrosion and the Fe dissolution rate in steels. More than 40 wt.% of the 20 µm-thick galvanized zinc layer was dissolved after one week of immersion in 0.5 M sodium chloride or sodium acetate. After this one-week immersion, or the 10-week atmospheric field exposure, any remaining zinc was entirely in the form of zinc oxide. Our findings call for further investigation before using organic de-icing salts, alone or in mixtures with NaCl, on galvanized steel.
|
May 2026
|
|
I11-High Resolution Powder Diffraction
|
Diamond Proposal Number(s):
[39378]
Open Access
Abstract: Realizing net-zero emissions demands the design of innovative and efficient catalysts for CO2 valorization. Herein, we report a core@shell-structured catalyst precursor, h-ZrO2@Cu1.3ZnAl1.6-LDH, in which layered double hydroxide (LDH) platelets are arranged around hollow zirconia spheres (h-ZrO2), maximizing the interfacial area between the active LDH component and zirconia promoter. The h-ZrO2@Cu1.3ZnAl1.6-LDH-derived catalyst efficiently converts CO2 into methanol, reaching space-time yields (STYs) comparable to commercial catalysts, despite a 54% reduction in Cu loading (0.59 gMeOH gcat−1 h−1 at 250 °C, 45 bar, H2/CO2 = 3, 18,000 mL g−1 h−1 weight hourly space velocity, WHSV). Reporting the STY on a per gram copper basis highlights the efficiency of the catalyst: h-ZrO2@Cu1.3ZnAl1.6-LDH is twofold more active than the commercial catalyst under the same conditions (2.7 vs 1.3 gMeOH gcat−1 h−1).
|
May 2026
|
|
B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
B18-Core EXAFS
|
Ainara
Aguadero
,
Federico
Baiutti
,
Monica
Burriel
,
Markus
Kubicek
,
Alexander Karl
Opitz
,
Juergen
Fleig
,
David
Munoz-Rojas
,
Christophe
Vallée
,
Marceline
Bonvalot
,
Alexia
Popescu
,
Nicola H
Perry
,
Francesco M.
Chiabrera
,
Álex
Morata
,
Juan Carlos
Gonzalez-Rosillo
,
Alexander
Stangl
,
Ramon
Escobar-Galindo
,
Mattias
Krause
,
Sivakkumaran
Sukumaran
,
Sarah
Fearn
,
Richard J.
Chater
,
Stephen J.
Skinner
,
John
Kilner
,
Sören
Möller
,
Martin
Finsterbusch
,
Manoj Kumar
Ghosalya
,
Samuli
Urpelainen
,
Christoph
Baeumer
,
Santosh
Kumar
,
Veronica
Celorrio
,
Diego
Gianolio
,
David C.
Grinter
,
Pilar
Ferrer-Escorihuela
,
Georg
Held
,
Jordi
Cabana
,
Sandrine
Lyonnard
,
Dorthe
Bomholdt Ravnsbaek
,
M. Rosa
Palacin
,
Montserrat
Casas-Cabanas
,
Julie
Villanova
,
Aline
Léon
,
Qiucheng
Xu
,
Jakub
Drnec
,
Brian
Seger
,
David R
Diercks
,
Nejc
Hodnik
,
Lluís
Yedra
,
Sonia
Estrade
,
Francesca
Peiró
,
Neus
Domingo
,
Maciej O
Liedke
,
Enric
Menéndez
,
David J.
Keeble
,
Jakub
Čížek
,
Ralf F.
Ziesche
,
Oriol
Sans Planell
,
Nikolay
Kardjilov
,
Ingo
Manke
,
Daniele
Pergolesi
,
Jochen
Stahn
Open Access
Abstract: A strong societal and political drive is motivating the development and optimization of novel
energy
conversion and storage systems for decarbonization. The successful implementation of solid
state devices such as fuel cells and secondary batteries depends, however, on achieving
ambitious targets in terms of performance, reliability and cost competitiveness. Research and
technology are addressing these needs through a holistic approach including exploration of new
materials and nanoarchitectures, as well as system engineering. These significant efforts require
the support of appropriate characterization tools capable of assessing nanometer-scale
phenomena such as concentration profiles of ionic and electronic charges, local chemical
compositions and their evolution over time across interfaces.
This roadmap provides an overview of selected advanced characterization techniques for
energy materials and devices. Specific focus is put on in situ/operando methods for probing
electrochemical phenomena in real-time under realistic working conditions. Experts in the field
provide an extensive review of the current state of the art in 2025 and the current and future
challenges for the characterization of local chemistry and kinetics in the bulk of the material, in
nanoarchitectures (e.g. thin films) and at the interfaces (e.g. grain boundaries, phase contacts,
solid/liquid and solid/gas interfaces) . The aim is to provide a detailed guide to the techniques,
describing opportunities and bottlenecks for their practical deployment and examples of
successful
applications.
|
May 2026
|
|
I12-JEEP: Joint Engineering, Environmental and Processing
|
Abstract: Amid rising global demand for renewable energy and effective plastic waste management, adopting green methods to utilize plastic waste for chemicals is a win–win strategy. Constituting the largest amount of single-use plastic litter worldwide, cellulose diacetate (CDA) based waste cigarette filters urgently require sustainable valorization pathways. However, CDA photoconversion remains highly challenging due to substantial energy barriers for selective bond cleavage, inadequate radical generation capability, and inefficient charge-carrier separation. Herein we propose a strategy to efficiently obtain C2H4 through carbene-mediated CDA photoconversion by using a sulfur vacancy-regulated copper-gallium-zinc-sulfide (VS-CGZS) catalyst. VS-CGZS enhances the thermal effect of light and lowers the energy barrier for acetyl group (*CH3CO) desorption from CDA. VS reduces the adsorption energy of *CH3CO on VS-CGZS and facilitated :CH2 formation. Consumption of photogenerated holes via *CH3CO desorption and VS-enhanced carrier separation synergistically elevate the photogenerated electrons concentration for :CH2 coupling, thereby selectively triggering and boosting C2H4 yield. Therefore, we achieve a record-breaking 14.43 mmol·gcat–1 C2H4 for CDA photoconversion within 4 h, over 6 times exceeding previous reports on photoconverting plastic into C2H4. This work establishes a strategy for efficient ethylene production from photoconversion of cellulose diacetate and carves out a paradigm in solar-driven plastic valorization.
|
May 2026
|
|
