I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[35696]
Open Access
Abstract: The significant influence of nanoparticle (NP) size and morphology on their physical and chemical properties has been extensively investigated in recent decades. However, equating morphology solely with the overall shape overlooks finer surface characteristics. In this study, we introduce an advanced shape-fitting technique for the precise and automated extraction of NP characteristics from standard TEM images. This method captures detailed descriptors beyond size and shape, such as aspect ratio and radius of curvature, while maintaining statistical significance. Applying this approach, we identified a subtle difference in corner roundness between two batches of iron oxide nanocubes with identical size and aspect ratio distributions, synthesized consecutively under the same conditions. Yet, we report pronounced disparities in their magnetic properties and hyperthermia behavior. After ruling out internal variations through Mössbauer and X-ray absorption spectroscopies, these discrepancies are attributed to the slight morphological differences between the nanocubes via surface spin disorder. Beyond providing a thorough reproducibility assessment, our findings underscore the critical importance of precise morphological characterization in establishing reliable shape–property relationships, essential for informed NP design and adherence to good manufacturing practices.
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May 2026
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I10-Beamline for Advanced Dichroism - scattering
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Margaret A.
Anderson
,
Megan E.
Goh
,
Yang
Zhang
,
Kyeong-Yoon
Baek
,
Michael
Schulze
,
Mario
Brützam
,
Christoph
Liebald
,
Chris
Lygouras
,
Dan Ferenc
Segedin
,
Aaron M.
Day
,
Zubia
Hasan
,
Donald A.
Walko
,
Hua
Zhou
,
Peter
Bencok
,
Alpha T.
N'Diaye
,
Charles M.
Brooks
,
Ismail
El Baggari
,
John T.
Heron
,
S. M.
Koohpayeh
,
Daniel
Rytz
,
Christo
Guguschev
,
Julia A.
Mundy
Diamond Proposal Number(s):
[41817]
Abstract: he pyrochlore vanadates are compelling candidates for next-generation dissipationless devices.
and
are ferromagnetic insulators (T
70 K) that are believed to exhibit the magnon Hall effect and are expected to host topological magnons. Their completely dissipationless magnon edge states could be harnessed to realize low-power information transport in spintronic or magnonic devices. As a crucial step in the realization of devices, we synthesize the first thin films of pyrochlore
on isostructural
substrates and explore the evolution of their magnetic properties down to the ultrathin limit. All films are insulating ferromagnets with transition temperatures of up to the bulk value (T
68 K) that decrease with thickness according to finite-size effects. Our films also exhibit a change in anisotropy from in-plane to out-of-plane easy axis coincident with the development of partial strain relaxation and nonzero magnetic hysteresis in an applied field. This evolution demonstrates the impact of strain on magnetic anisotropy and paves the way to tunable magnon topology.
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Mar 2026
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B18-Core EXAFS
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Biswajit
Bhattacharyya
,
Christian
Balischewski
,
Jiyong
Kim
,
Tiago
Duarte
,
Lianshe
Fu
,
Rute A.s.
Ferreira
,
Alkit
Beqiraj
,
Iuliia
Mikulska
,
Diego
Gianolio
,
Eric
Sperlich
,
Felix
Stete
,
Wouter
Koopman
,
Christina
Günter
,
Katlen
Brennenstuhl
,
Daniel
Van Opdenbosch
,
Cordt
Zollfrank
,
Armin
Wedel
,
Beth J.
Murray
,
Małgorzata
Swadźba-Kwaśny
,
Tillmann
Klamroth
,
Michael U.
Kumke
,
Verónica
De Zea Bermudez
,
Andreas
Taubert
Open Access
Abstract: Low-melting ionic solids with stirring luminescent properties hold significant promise for optoelectronic applications. Here, we compare and contrast the structural and spectroscopic correlations of two highly luminescent organic-inorganic manganese halides (C4Py)2[MnCl4] and (C4Py)2[MnBr4], synthesized from their respective manganese halides and N-butyl pyridinium halide ionic liquids. Although both compounds exhibit very similar bulk structures (determined by single-crystal and powder X-ray diffraction) and overall similar electronic structures (as indicated by the density of states), they differ notably in their optical properties. The chloride salt, (C4Py)2[MnCl4], has a photoluminescence decay lifetime ten times longer than its bromide analogue, (C4Py)2[MnBr4]. Furthermore, PL-quantum yield of (C4Py)2[MnBr4] is 1.6 times higher than that of (C4Py)2[MnCl4], which was attributed to the heavy atom effect of bromine atoms, based on periodic density functional calculations (with and without spin-orbit coupling). Although photoluminescence is only exhibited in the solid state, EXAFS analysis confirms that the coordination environment of manganese is remarkably similar in crystalline and molten states, potentially suggesting that photoluminescence is associated with the long-range crystalline order, which is lost upon melting. Building on these fundamental studies, the potential of (C4Py)2[MnCl4] as a luminescent security ink for anticounterfeiting applications has been demonstrated.
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Feb 2026
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E02-JEM ARM 300CF
I05-ARPES
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Amy
Carl
,
Nicholas
Clark
,
David G.
Hopkinson
,
Matthew
Hamer
,
Matthew
Watson
,
Laxman
Nagireddy
,
James E.
Nunn
,
Alexei
Barinov
,
Yichao
Zou
,
William
Thornley
,
Casey
Cheung
,
Wendong
Wang
,
Sam
Sullivan-Allsop
,
Xiao
Li
,
Astrid
Weston
,
Eli G.
Castanon
,
Andrey V.
Kretinin
,
Cephise
Cacho
,
Neil R.
Wilson
,
Sarah J.
Haigh
,
Roman
Gorbachev
Diamond Proposal Number(s):
[21597, 21981, 24290, 24338]
Open Access
Abstract: Magnetic two-dimensional materials are a promising platform for novel nano-electronic device architectures. One such layered crystal is the ferromagnetic semiconductor chromium germanium telluride (Cr2Ge2Te6) which recently attracted interest due to its potential for spintronics and memory applications. Here we investigate its properties from the structural standpoint using atomic resolution Scanning Transmission Electron Microscopy (STEM) and present the first atomic resolution images down to its monolayer limit. We develop a novel technique that allows one to map the local tilt with unprecedented spatial resolution using only high-resolution images, enabling mapping of the topography and morphological variation of atomically thin crystals. Using it, we show that the Cr2Ge2Te6 monolayer has an unusually large out-of-plane rippling, with local tilt variation reaching 20° over few nm length scales. We hypothesize that such a strongly buckled structure originates from both point and extended lattice defects which are more prevalent in monolayer crystals. In addition, we correlate the structural observations with the band structure measurements using Angle-Resolved Photoemission Spectroscopy (ARPES). We believe that both the atomic scale insights we have gained on Cr2Ge2Te6 and our novel approach to nanoscale topography mapping will benefit the development of van der Waals heterostructures in both fundamental and applied research.
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Feb 2026
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B18-Core EXAFS
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Run
Ran
,
Haoliang
Huang
,
Qingqing
Chen
,
Fei
Lin
,
Zhipeng
Yu
,
Weifeng
Su
,
Chenyue
Zhang
,
Qingsen
Jia
,
Jingwei
Wang
,
Yang
Zhao
,
Kaiyang
Xu
,
Binwen
Zeng
,
Yaowen
Xu
,
Weimian
Zhang
,
Zhijian
Peng
,
Lifeng
Liu
Diamond Proposal Number(s):
[36104]
Abstract: Sulfur quantum dots (SQDs) represent an emerging class of metal-free, biocompatible luminescent nanomaterials, yet their synthesis remains challenged by harsh conditions, high energy consumption, and limited scalability. Herein, we report a highly value-added strategy coupling SQD synthesis with hydrogen production through sulfion (S2−) oxidation reaction (SOR) assisted alkaline-modified seawater electrolysis (SWE). Such coupling substantially lowers the energy demand for electrolysis and effectively circumvents the interfering chlorine evolution at the anode. An efficient and stable cobalt single-atom catalyst (Co-SAs-PNC) is developed to boost SOR, achieving a large current density of 500 mA cm−2 at 0.536 V vs. reversible hydrogen electrode in alkaline-modified natural seawater and operating stably for 116 h. A flow cell comprising Co-SAs-PNC as the anode catalyst and commercial Pt/C as the cathode catalyst requires only 1.01 V to reach 500 mA cm−2 and shows outstanding durability of >450 h. Besides valuable hydrogen generated at the cathode, the polysulfides electrochemically derived at the anode can be readily converted to multicolor photoluminescent SQDs. Comprehensive in situ/operando experiments and theoretical calculations elucidate the SOR mechanism at isolated Co sites. This work not only opens a new avenue for sustainable SQD production but also remarkably enhances the economic viability of the SWE technology.
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Jan 2026
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B18-Core EXAFS
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Abstract: The large-scale deployment of proton exchange membrane water electrolyzers (PEMWEs) is hindered by the scarcity and instability of iridium-based oxides (IrOx) catalysts during the acidic oxygen evolution reaction. Herein, we report a dynamic embedding strategy to construct highly stable and active low-iridium catalysts, which enables controlled incorporation of IrOx nanoclusters (NCs) into an amorphous TiOx overcoating supported on carbon nanotubes (IrOx/TiOx@CNT). Combined experimental and theoretical studies reveal that the dynamic embedding process enables coordinated growth kinetics, facilitating continuous anchoring of IrOx NCs within the flexible amorphous TiOx matrix. The resulting strong IrOx-TiOx interaction promotes significant electron transfer from TiOx to IrOx, thereby optimizing the adsorption energetics of oxygen intermediates and suppressing IrOx dissolution. The optimized catalyst achieves an exceptionally low overpotential of 258 mV at 10 mA cm−2 and outstanding durability in 0.5 m H2SO4. In PEMWE, the catalyst enables a cell voltage of 1.70 V at 1.0 A cm−2 with an ultralow Ir loading (0.3 mg cm−2), coupled with low energy consumption (45 kWh kg−1 H2) and hydrogen production cost (∼$0.9 kg−1 H2). This work underscores the pivotal role of amorphous overlayers in creating dynamically stable interfaces for advanced electrocatalysis.
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Jan 2026
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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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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
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Diamond Proposal Number(s):
[35956]
Abstract: Electrocatalytic water splitting is a sustainable route to high-purity hydrogen, yet its efficiency is hindered by the sluggish kinetics of the oxygen evolution reaction (OER). Replacing OER with the thermodynamically favorable ammonia oxidation reaction (AOR) significantly reduces the energy input required for hydrogen production while simultaneously addressing ammonia utilization. However, progress is limited by the need for expensive noble metal catalysts like PtIr/C and the poor performance of non-noble alternatives. Herein, a series of perovskite oxide catalysts is reported with tunable B-site configurational entropy. Among them, the high-entropy La0.7Sr0.3(Ni0.2Cu0.2Co0.2Mn0.2Fe0.2)O3-δ (LS5B) catalyst demonstrates exceptional activity and stability for the ammonia-water co-oxidation reaction (AWOR), outperforming lower-entropy analogs. The enhanced performance is attributed to its entropy-stabilized structure, which generates abundant surface oxygen vacancies and suppresses atomic diffusion, increasing both active site density and structural durability. Density functional theory (DFT) calculations reveal that the high-entropy configuration lowers the energy barrier for ammonia adsorption and facilitates intermediate formation. In a practical ammonia-water co-electrolyzer, LS5B delivers a current density of 2.6 A·cm−2 at 2.0 V, surpassing PtIr/C and representing the best performance to date. A stable operation over 90 h at ampere-level current demonstrates LS5B's potential for scalable, efficient green hydrogen production via ammonia-water co-electrolysis.
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Nov 2025
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I06-Nanoscience (XPEEM)
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Lingzhi
Wen
,
Cong
Li
,
Guanshihan
Du
,
Sijie
Wu
,
Jianbing
Zhang
,
Xiaoyin
Pan
,
Clodomiro
Cafolla
,
Lizhe
Hu
,
Yongjun
Wu
,
Zijian
Hong
,
Qing
He
,
Pu
Yu
Diamond Proposal Number(s):
[42042, 36503, 34602, 26142, 22361, 38419]
Abstract: Topological polar textures have garnered significant attention for next-generation electronic devices due to associated emergent functionalities (e.g., chirality, enhanced conductivity, and negative capacitance). Most studies stabilize topological textures using depolarization field in ferroelectric- dielectric superlattices or heterostructures; however, the lack of direct electrical contacts dramatically hinders the corresponding field-driven control and applications. Here, the formation of electric-field-switchable Néel-type polar skyrmions at room temperature is demonstrated in Ba0.8Sr0.2TiO3 (BSTO) thin films directly grown on metallic SrRuO3 electrodes. In this study, strategic Sr substitution is employed to engineer the Landau energy landscape of ferroelectric material BaTiO3, which eventually facilitates the coexistence of multiple polarization states without sacrificing room-temperature ferroelectricity. Piezoelectric force microscopy (PFM) uncovers a critical BSTO thickness to host the phenomena: conventional ferroelectric domains dominate 60-nm thick BSTO, whereas high-density topological polar textures emerge in 10-nm thick BSTO. Specifically, vector-PFM analysis identifies two stable skyrmion states in 10-nm BSTO with convergent- and divergent- in-plane polarization components. Importantly, an electric-field-driven interconversion between these topological states is demonstrated by reconfiguring the free-energy landscape, which is also supported by the phase-field simulations. This work provides a direct pathway of using metallic electrodes for the dynamic control of topological ferroelectrics in functional devices.
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Nov 2025
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I09-Surface and Interface Structural Analysis
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Diamond Proposal Number(s):
[29113]
Open Access
Abstract: LiNi0.5Mn1.5O4 (LNMO) cathodes offer a cobalt-free, high-voltage alternative to current state-of-the-art Li-ion battery cathodes, and are particularly well-suited for high-power applications due to their 3D lithium-ion pathways and structural stability. However, degradation of commercial electrolytes at high voltages exacerbates capacity decay, as instability at the cathode surface causes active material loss, surface reconstructions, thickening surface layers, and increases in internal cell resistance. Cationic substitution has been proposed to enhance surface stability, thus limiting capacity decay. Here, we demonstrate the stabilizing effect of Mg on the LNMO cathode surface, which is most evident during the early stages of cycling. This study indicates that improved O 2p-TM 3d hybridization in Mg-substituted LNMO, facilitated by Li-site defects, leads to the formation of a stable surface layer that is corrosion-resistant at high voltage. Examination of Fe-substituted and unsubstituted LNMO further confirms that the surface stability is uniquely enabled by Mg substitution. This work offers valuable insights into surface design for reducing degradation in high-voltage spinel cathodes.
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Nov 2025
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