B18-Core EXAFS
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Diamond Proposal Number(s):
[39912]
Open Access
Abstract: Copper (Cu) is a recyclable, abundant, and promising catalyst for energy transition reactions like electrochemical conversion of nitrate (NO₃RR) and CO2 electroreduction. However, conventional Cu-based electrocatalysts struggle with activity, selectivity, and durability, especially under harsh electrochemical conditions. Exsolution—the in-situ generation of metallic nanoparticles on oxide supports in a single step—enables tightly anchored, size-controlled particles, enhancing stability and performance. Incorporating Cu into Sr1-α(Ti, Fe)O₃-γ perovskites, an earth-abundant system with promising ionic-electronic conductivity and adequate oxygen vacancies, overcomes the limitations of traditional Sr(Ti, Fe)O₃ in facilitating nanoparticle exsolution. This work demonstrates controlled Cu nanoparticle exsolution from Sr₀.₉₅Ti₀.₃Fe₀.₇₋ₓCuₓO₃₋ᵧ perovskites at temperatures as low as 400°C, notably milder than conventional exsolution conditions. By systematically varying reduction parameters, we achieve control over nanoparticle size (13-38 nm) and population density (118-650 particles/μm²). Electrochemical characterisation using nitrate reduction as a probe reaction demonstrates how exsolution conditions directly influence surface reactivity, establishing these materials as tuneable platforms for (electro)catalytic applications.
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Dec 2025
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Open Access
Abstract: Nanostructured single-phase metal crystals with single and well-defined crystal structures exhibit unique, predictable, and stable properties that are distinct from those of multiphase crystals. However, synthesizing such pure nanocrystals is challenging, as bismuth exhibits multiple polymorphs and crystal phases that often prevent achieving monophase crystals, especially under atmospheric pressure. In this study, we present a gas-phase synthesis method using non-equilibrium plasma to produce high-purity, monophase bismuth nanocrystals (BiNCs) at atmospheric pressure. This approach employs a solid bismuth precursor, eliminating the need for hazardous solvents and offering a safer, more environmentally friendly alternative. By controlling plasma absorbed power and incorporating hydrogen to the process gas, localized melting and surface nucleation are promoted, resulting in the formation of BiNCs with a rhombohedral crystal phase. High-resolution transmission electron microscopy, X-ray diffraction and Raman spectroscopy confirmed the crystallinity of the BiNCs, exhibiting sharp faceting in some cases. X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy revealed that the nanocrystals were predominantly composed of elemental bismuth with minimal surface oxidation when exposed to the atmosphere.
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Nov 2025
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I07-Surface & interface diffraction
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Dario
Mastrippolito
,
Ashkan
Shahmanesh
,
Mariarosa
Cavallo
,
Erwan
Bossavit
,
Iman
Laqchaa El Abed
,
Corentin
Dabard
,
Shalini
Singh
,
Mathieu
Silly
,
Francesco
Capitani
,
Nemanja
Peric
,
Louis
Biadala
,
Andrea
Zitolo
,
Jose
Avila
,
Francesco
Carla
,
Cesare
Tresca
,
Emmanuel
Lhuillier
,
Benoit
Mahler
,
Debora
Pierucci
Diamond Proposal Number(s):
[38497]
Abstract: Controlling the crystal phase of two-dimensional transition metal dichalcogenides (TMDs) is essential for tailoring their electronic and optical properties. Among the polymorphs of WS2, the metastable 1T′ phase exhibits semimetallic or narrow-bandgap character and hosts quantum functionalities distinct from the semiconducting 1H phase. Here, we investigate the temperature-induced 1T′/1H phase transition in colloidally synthesized monolayer WS2 nanosheets functionalized with organic ligands. The reducing conditions of the synthesis stabilize the 1T′ phase via electron doping. Through in situ analyses of both the structural and electronic properties, we monitor the phase evolution during annealing and find that the 1T′ phase remains stable up to 300 °C, accompanied by a relative lattice contraction. Between 300 and 350 °C, a mixed 1T′/1H regime appears, where the 1H content can be finely tuned by controlling the annealing time. Above 350 °C, a rapid and complete transformation to the 1H phase occurs. We demonstrate that the decomposition of the reducing ligand serves as the primary trigger of the structural transition, revealing a strong interplay among doping, surface chemistry, and lattice structure. Notably, nanosheets with smaller lateral dimensions exhibit slower phase transition kinetics, suggesting that finite size could influence the structural rearrangement underlying the phase transformation.
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Oct 2025
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I09-Surface and Interface Structural Analysis
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Ali
Sufyan
,
Tyler
James
,
Connor
Fields
,
Shabnam
Naseri
,
Filipe L. Q.
Junqueira
,
Sofia
Alonso Perez
,
Sally
Bloodworth
,
Gabriella
Hoffman
,
Mark C.
Walkey
,
Elizabeth S.
Marsden
,
Richard J.
Whitby
,
Yitao
Wang
,
David A.
Duncan
,
Tien-Lin
Lee
,
James N.
O'Shea
,
Andreas
Larsson
,
Brian
Kiraly
,
Philip
Moriarty
Diamond Proposal Number(s):
[31574]
Open Access
Abstract: Core-level and tunnelling spectroscopies applied to noble gas endofullerenes offer complementary insights into electron transfer rates, addressing both intramolecular and extramolecular processes. Elastic and inelastic tunnelling spectroscopy of empty C60 and Kr@C60 on Pb/Cu(111) each show that the encapsulated atom is essentially invisible to scanning probes. We interpret the lineshape of the lowest unoccupied molecular orbital (LUMO) of Pb-adsorbed (endo)fullerenes in tunnelling spectra as a signature of the dynamic Jahn-Teller (DJ-T) effect. This effect persists in electronically decoupled second-layer molecules, which also display distinct vibronic progressions in on-resonance tunnelling. DFT calculations reproduce the LUMO alignment and low density of states at the Fermi level seen in experimental tunnelling spectra for (endo)fullerenes on Pb, and, in line with submolecular resolution STM images, also predict that an atom-down orientation of the fullerene cage is energetically most favourable (although other adsorption geometries differ only by tens of meV at most). In contrast to the tunnelling data, core-level-focussed techniques -namely, photoemission, X-ray absorption, and resonant Auger-Meitner electron spectroscopy -of Ar@C60/Pb(111) indicate that the encapsulated atom is heavily coupled to the molecular environment, with both a clear influence of substrate screening on the core-level lineshape and the absence of spectator signal in decay spectra.
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Oct 2025
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I05-ARPES
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Nicolai
Taufertshöfer
,
Corinna
Burri
,
Rok
Venturini
,
Iason
Giannopoulos
,
Sandy Adhitia
Ekahana
,
Enrico
Della Valle
,
Anže
Mraz
,
Yevhenii
Vaskivskyi
,
Jan
Lipič
,
Alexei
Barinov
,
Dimitrios
Kazazis
,
Yasin
Ekinci
,
Dragan
Mihailovic
,
Simon
Gerber
Open Access
Abstract: In-operando characterization of van der Waals (vdW) devices using surface-sensitive methods provides critical insights into phase transitions and correlated electronic states. Yet, integrating vdW materials in functional devices while maintaining pristine surfaces is a key challenge for combined transport and surface-sensitive experiments. Conventional lithographic techniques introduce surface contamination, limiting the applicability of state-of-the-art spectroscopic probes. We present a stencil lithography-based approach for fabricating vdW devices, producing micron-scale electrical contacts, and exfoliation in ultra-high vacuum. The resist-free patterning method utilizes a shadow mask to define electrical contacts and yields thin flakes down to the single-layer regime via gold-assisted exfoliation. As a demonstration, we fabricate devices from 1T-TaS2 flakes, achieving reliable contacts for application of electrical pulses and resistance measurements, as well as clean surfaces allowing for angle-resolved photoemission spectroscopy. The approach provides a platform for studying the electronic properties of vdW systems with surface-sensitive probes in well-defined device geometries.
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Aug 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[34358]
Open Access
Abstract: Heterogeneous catalysts are often undergoing subtle structural changes in both the nanoparticle and the support phase during operation conditions. Catalytic cycling in in-situ experiments between catalysis and dropout conditions allows for exploiting the power of modulation excitation (ME) experiments. While phase sensitive detection (PSD) of ME experiments has been showcased for infrared and X-ray absorption spectroscopy in the past, here we present the first application to pair distribution function (PDF) analysis. We have performed in-situ X-ray total scattering studies on two alumina supported nickel catalysts (Ni@alumina) under methanation condition and hydrogen dropouts, and showcase how PSD analysis of the modulation excitation pair distribution function (ME-PDF) data improves the signal-to-noise ratio in the phase-resolved PDF data, enabling us to detect otherwise hidden structural changes. We identify a metal-support interaction of the Ni nanoparticles with the γ-Al2O3 support when choosing the deposition-precipitation method for catalyst preparation. By way of contrast, an industrial catalyst with comparable catalytic performance and nanoparticle diameters showed a dynamic surface oxidation of Ni nanoparticles during unstable H2 supply.
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Jul 2025
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B21-High Throughput SAXS
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Diamond Proposal Number(s):
[30763]
Open Access
Abstract: Metal nanocrystals (M-NCs) and their supramolecular assemblies have attracted significant interest from the scientific community due to their wide range of applications arising from the possibility of accurately tuning the M-NCs properties through self-assembly into supramolecular aggregates. In this study, we investigate the complex interplay between capping agent surface coverage and solvent-capping agent interactions in the self-assembly process of M-NCs into supramolecular structures. Specifically, we explore the self-assembly behavior of gold (Au-NCs), silver (Ag-NCs), and platinum (Pt-NCs) nanocrystals upon functionalization with oleic acid (OA) in water using a microemulsion approach. Through a multi-technique analysis, we demonstrate the critical role of ligand density and solvent choice in driving the formation of highly ordered supramolecular structures. By increasing the surface coverage of the M-NC ligands, we observed a transition to more organised assemblies, with the interaction between the oleylamine alkyl chain and the functionalization medium further modulating the type of supramolecular arrangement. Moreover, we highlight the profound influence of both the external environment and supramolecular aggregation on the optical properties of the M-NCs. This work provides crucial insights into the factors that govern nanocrystals’ self-assembly and optical behavior, with broad implications for the design and application of nanomaterials in nanotechnology and materials science.
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Jun 2025
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I09-Surface and Interface Structural Analysis
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Francesco
Offi
,
Francesco
Borgatti
,
Pasquale
Orgiani
,
Vincent
Polewczyk
,
Sandeep Kumar
Chaluvadi
,
Shyni
Punathum Chalil
,
Aleksandr
Petrov
,
Federico
Motti
,
Gian Marco
Pierantozzi
,
Giancarlo
Panaccione
,
Bogdan
Rutkowski
,
Paolo
Mengucci
,
Gianni
Barucca
,
Deepnarayan
Biswas
,
Tien-Lin
Lee
,
Emiliano
Marchetti
,
Alberto
Martinelli
,
Davide
Peddis
,
Gaspare
Varvaro
Diamond Proposal Number(s):
[32921]
Open Access
Abstract: Epitaxial heterostructures integrating thin Fe3O4 films hold great potential for spintronics, magnetoionics, and multifunctional device development. In this work, the morpho-structural and magnetic properties of all-spinel Fe3O4/MgCr2O4/Fe3O4 trilayers grown on a MgCr2O4 buffer-layer, exhibiting very close lattice matching, were investigated by using both surface and bulk sensitive techniques. The close lattice match between Fe3O4 and MgCr2O4 enables the growth of epitaxial heterostructures with magnetically decoupled Fe3O4 layers for spacer thicknesses ≥ 1.6 nm, while reducing the formation of antiphase boundaries. Despite localized interphase diffusion, which leads to the formation of a mixed Cr/Fe spinel oxide with magnetically polarized Cr ions at the Fe3O4/MgCr2O4 interfaces, the overall magnetic properties remain largely consistent with those of the individual Fe3O4 layers. This study sheds light on the magnetic interactions within Fe3O4 layers mediated by a MgCr2O4 spacer, and demonstrates the feasibility of the approach in preserving the properties of thin Fe3O4 films, in complex heterostructures, thus offering a promising pathway for designing advanced all-spinel oxide devices.
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May 2025
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B18-Core EXAFS
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Pengwei
Wang
,
Peixi
Cong
,
Jiachen
Chen
,
Huaiyuan
Cao
,
Qi
Yue
,
Zixiao
Xue
,
Junji
Zhang
,
Long
Zhang
,
Robert S.
Weatherup
,
Jiabin
Cui
,
Jin
He
Diamond Proposal Number(s):
[31218]
Abstract: The confined synthesis of carbon dots (CDs) in solid matrixes is a promising avenue for developing new afterglow materials. Benefiting from the advantages of the sol–gel preparation of nanoporous glass, we report transparent glass-confined CDs with tunable afterglow luminescence. Switchable thermally-activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) of CDs were achieved by adjusting the sintering temperature and ion doping. Our findings reveal that with an increase in sintering temperature from 500 °C to 600 °C, the energy gap (ΔEST) of CD-nanoporous glass (NG) increased from 0.05 eV to 0.21 eV, while the lifetime increased from 329 ms to 548 ms, which is attributed to the enhanced carbonization degree of the CDs. Pb2+ doping is also shown to achieve switchable TADF and RTP of glass-confined CDs attributed to the alteration of interfacial interactions between the glass and confined CDs. This design concept introduces a new perspective for developing transparent afterglow materials for various unique phosphorescence applications.
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Mar 2025
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Peng
Chen
,
Jieyi
Liu
,
Yifan
Zhang
,
Puyang
Huang
,
Jack
Bollard
,
Yiheng
Yang
,
Ethan L.
Arnold
,
Xinqi
Liu
,
Qi
Yao
,
Fadi
Choueikani
,
Gerrit
Van Der Laan
,
Thorsten
Hesjedal
,
Xufeng
Kou
Abstract: MnBi2Te4-based superlattices not only enrich the materials family of magnetic topological insulators, but also offer a platform for tailoring magnetic properties and interlayer magnetic coupling through the strategic insertion layer design. Here, we present the electrical and magnetic characterization of (Bi1−xSbx)2Te3-intercalated MnBi2Te4 multilayers grown by molecular beam epitaxy. By precisely adjusting the Sb-to-Bi ratio in the spacer layer, the magneto-transport response is modulated, unveiling the critical role of Fermi level tuning in optimizing the anomalous Hall signal and reconfiguring the magnetic ground state. Moreover, by varying the interlayer thickness, tunable magnetic coupling is achieved, enabling precise control over ferromagnetic and antiferromagnetic components. These findings pave the way for the exploration of versatile magnetic topological phases in quantum materials systems.
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Feb 2025
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