B18-Core EXAFS
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Diamond Proposal Number(s):
[39179]
Open Access
Abstract: Developing photocatalysts that can efficiently utilize the full solar spectrum is a crucial step toward transforming sustainable energy solutions. Due to their light absorption limitations, most photo-responsive metal−organic frameworks (MOFs) are constrained to the ultraviolet (UV) and blue light regions. Expanding their absorp-tion to encompass the entire solar spectrum would unlock their full potential, greatly enhancing efficiency and applicability. Here, we report the design and synthesis of a series of highly stable boron-dipyrromethene (bodipy) based MOFs (BMOFs) by reacting dicar-boxyl-functionalized bodipy ligands with Zr-oxo clusters. Leveraging the acidity of the methyl groups on the bodipy backbone, we ex-panded the conjugation system through a solid-state condensation reaction with various aldehydes, achieving full-color absorption, thereby extending the band edge into the near-infrared (NIR) and infrared (IR) regions. These BMOFs demonstrated exceptional reac-tivity and recyclability in heterogeneous photocatalytic activities, including C−H bond activation of saturated aza-heterocycles and C−N bond cleavage of N,N-dimethylanilines to produce amides under visible light. Our findings highlight the transformative potential of BMOFs in photocatalysis, marking a significant leap forward in the design of advanced photocatalytic materials with tunable properties.
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Apr 2025
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B07-B1-Versatile Soft X-ray beamline: High Throughput ES1
B18-Core EXAFS
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Diamond Proposal Number(s):
[32514]
Open Access
Abstract: Fe/N/C based catalysts are the best positioned ones to replace the state-of-the-art Pt-based catalysts for the oxygen reduction reaction (ORR) in Proton Exchange Membrane Fuel Cells (PEMFCs). Here, a Fe/N/C catalyst characterized by a high N/C ratio, has been synthesized from the pyrolysis of a N-rich imine-based polymer. In acidic electrolyte (0.1 M HClO4). The catalyst demonstrates notable ORR activity with Eonset and E1/2 values of 1.09 and 0.77 V vs. RHE, respectively. Furthermore, the catalyst’s performance has been assessed in a single cell PEMFC setup. The optimization of the membrane electrode assembly (MEA) with the Fe/N/C catalyst entails examining various ionomer to catalyst ratios (I/C) as well as two coating methods: spray coating and drop casting. The optimized MEA achieved a cell performance of 725 mA cm-2 at 0.3 V and a power density close to 220 mW cm-2. In order to understand the factors influencing PEMFC polarisation curves, electrochemical impedance spectroscopy (EIS) was performed under potentiostatic conditions. The effect of operational parameters, such as ionomer to catalyst ratios (I/C) and the use of either O2 or air at the anode feed, has been investigated. EIS spectra allow the calculation of the distribution of relaxation times (DRT), providing insights into the rate and resistance of the ORR process occurring at the MEA. Notably, the cathode with an I/C=2, prepared by drop casting, exhibited superior performance attributed to reduced ORR resistances. The current density and power density reached with the 25 cm2 MEA are comparable to those obtained with the 5 cm2 MEA using O2 as cathode reactant.
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Apr 2025
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B18-Core EXAFS
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Yaowen
Xu
,
Kaiyang
Xu
,
Hao
Tan
,
Haoliang
Huang
,
Fei
Lin
,
Chenyue
Zhang
,
Jingwei
Wang
,
Run
Ran
,
Zhipeng
Yu
,
Sitaramanjaneya Mouli
Thalluri
,
Lijian
Meng
,
Dehua
Xiong
,
Lifeng
Liu
Diamond Proposal Number(s):
[36104]
Abstract: The development of efficient and durable electrocatalysts for the oxygen evolution reaction (OER) is critical to advancing anion exchange membrane water electrolysis (AEMWE) technology for sustainable hydrogen production. Herein, we report the synthesis of multimetallic NiCrFeMo layered double hydroxides (LDHs) via a facile microwave-assisted hydrothermal approach, engineered as high-performance OER catalysts for AEMWE operating at industrially relevant current densities. Advanced X-ray absorption spectroscopy (XAS) studies demonstrate that the interplay of Ni, Cr, Fe, and Mo tailors the electronic structure and coordination environment. Consequently, the NiCrFeMo LDHs exhibit remarkable OER performance, achieving overpotentials of 236 and 387 mV at 10 and 500 mA cm⁻², respectively, in 1.0 M KOH, as well as outstanding durability at 500 mA cm-2 for 1000 hours with negligible degradation. In-situ differential electrochemical mass spectroscopy (DEMS) and density functional theory (DFT) analyses reveal that the OER taking place on NiCrFeMo LDHs follows the adsorbate evolving mechanism, with minimal lattice oxygen involvement, contributing to the catalyst’s longevity. When integrated into a prototype AEM electrolyzer cell as the anode catalysts, the cell demonstrates a current density of 1 A cm⁻² at a relatively low voltage of 1.87 V and operates at 0.5 A cm-2 for 100 hours without decay, highlighting the potential of NiCrFeMo LDHs for practical applications. This work elucidates the synergistic effects of multimetallic compositions in LDHs, offering a strategy for designing cost-effective, high-efficiency OER catalysts to support green hydrogen production on scale.
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Apr 2025
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I07-Surface & interface diffraction
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Rahul A.
Nambiar
,
David P.
Mcmeekin
,
Manuel
Kober Czerny
,
Joel A.
Smith
,
Margherita
Taddei
,
Pietro
Caprioglio
,
Amit
Kumar
,
Benjamin W.
Putland
,
Junke
Wang
,
Karim A.
Elmestekawy
,
Akash
Dasgupta
,
Seongrok
Seo
,
M. Greyson
Christoforo
,
Jin
Yao
,
Daniel J.
Graham
,
Laura M.
Herz
,
David
Ginger
,
Henry J.
Snaith
Diamond Proposal Number(s):
[33462]
Open Access
Abstract: Vacuum deposition of metal halide perovskite is a scalable and adaptable method. In this study, we adopt sequential evaporation to form the perovskite layer and reveal how the relative humidity during the annealing step, impacts its crystallinity and the photoluminescence quantum yield (PLQY). By controlling the humidity, we achieved a significant enhancement of 50 times in PLQY from 0.12% to 6%. This improvement corresponds to an increase in implied open-circuit voltage (Voc) of over 100 meV. We investigate the origin of this enhanced PLQY by combining structural, chemical and spectroscopic methods. Our results show that annealing in a controlled humid environment improves the organic and inorganic halides' interdiffusion throughout the bulk, which in turn significantly reduces non-radiative recombination both in the bulk and at the interfaces with the charge transport layers, which enhanced both the attainable open-circuit voltage and the charge carrier diffusion length. We further demonstrate that the enhanced intermixing results in fully vacuum-deposited FA0.85Cs0.15Pb(IxCl1−x)3 p-i-n perovskite solar cells (PSCs) with a maximum power point tracked efficiency of 21.0% under simulated air mass (AM) 1.5G 100 mW cm−2 irradiance. Additionally, controlled humidity annealed PSCs exhibit superior stability when aged under full spectrum simulated solar illumination at 85 °C and in open-circuit conditions.
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Mar 2025
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I22-Small angle scattering & Diffraction
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Xiaochen
Yang
,
Zhiming
Feng
,
Mustafa
Alshurafa
,
Ming
Yu
,
Andrew B.
Foster
,
Heng
Zhai
,
Tianmu
Yuan
,
Yiheng
Xiao
,
Carmine
D'Agostino
,
Ling
Ai
,
Maria
Perez-Page
,
Keenan
Smith
,
Fabrizia
Foglia
,
Adam
Lovett
,
Thomas S.
Miller
,
Jianuo
Chen
,
Peter M.
Budd
,
Stuart M.
Holmes
Diamond Proposal Number(s):
[36267]
Open Access
Abstract: High-temperature proton exchange membrane fuel cells (HT-PEMFCs) is regarded as a promising energy conversion system owing to simplified water management and enhanced tolerance to fuel impurities. However, phosphoric acid (PA) leaching remains a critical issue, diminishing energy density and durability, posing significant obstacle to the commercial development of HT-PEMFCs. To address this, composite membranes incorporating the carboxylic acid-modified polymer of intrinsic microporosity (cPIM-1) are designed as framework polymer, blended with polyvinylpyrrolidone (PVP) for HT-PEMFCs. The Lewis acid-base interactions between cPIM-1 and PVP created an extensive hydrogen-bonding network, improving membrane compatibility. The optimized microporous structure and multiple anchoring sites gave rise to “domain-limited” PA clusters, enhancing the capillary effect. Simultaneously, improved hydrophobicity synergistically optimizes catalytic interface, promoting continuous and stable proton transfer. The HT-PEMFCs based on PVP/cPIM-1 composite membrane achieved a peak power density of 1090.0 mW cm−2 at 160 °C, representing a 152% improvement compared to PVP/PES membrane. Additionally, it demonstrated excellent durability, with a voltage decay of 0.058 mV h−1 over 210 h of accelerated stress test corresponds to more than 5000 h of constant current density durability test. This study presents a promising strategy for the development of high-performance and durable novel membranes in various energy conversion systems.
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Mar 2025
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I14-Hard X-ray Nanoprobe
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Dominic
Blackburn
,
Nathan S.
Hill
,
Christopher J.
Wood
,
Tamilselvan
Velusamy
,
Balder A.
Nieto-Díaz
,
Caitlin
Woolley
,
Andy
Brown
,
Loukas
Zampelis
,
Trevor
Mcardle
,
Molly
Worth
,
Timothy
Thornber
,
Ibrahim
Albariqi
,
Rachel C.
Kilbride
,
Tingxiang
Yang
,
C. Neil
Hunter
,
Graham J.
Leggett
,
George
Koutsourakis
,
James C.
Blakesley
,
Fernando A.
Castro
,
David
Beynon
,
Trystan M.
Watson
,
Dumitru
Sirbu
,
David G.
Lidzey
Diamond Proposal Number(s):
[32789]
Open Access
Abstract: We fabricate a type of back-contact perovskite solar cell based on 1.5 μm-width grooves that are embossed into a plastic film whose opposing “walls” are selectively coated with either n- or p-type contacts. A perovskite precursor solution is then deposited into the grooves, creating individual photovoltaic devices. Each groove device is series-connected to its neighbors, creating minimodules consisting of hundreds of connected grooves. Here, we report on the fabrication of groove-based devices using slot-die coating to deposit the perovskite precursor and explore the structure of the perovskite in the grooves using a range of microscopy and spectroscopy techniques. Significantly, our devices do not contain any expensive or scarce elements such as indium, indicating that this technology is both sustainable and low-cost. Furthermore, all coating processes explored here were performed using roll-to-roll processing techniques. Our technology is therefore completely scalable and is consistent with high-throughput, low-cost manufacturing.
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Feb 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[33748, 35376]
Open Access
Abstract: We report that self-supporting mesoporous platinum 3D nanowires with a single diamond (SD) morphology and a high specific surface area of 40.4 m2 g–1 demonstrated enhanced stability toward the oxygen reduction reaction (ORR). These were found to be superior to commercially available carbon-supported Pt nanoparticles (Pt/C). After 1000 potential cycles, there was a 21% loss in surface area for SD-Pt, as compared with a 40.3% loss for Pt/C with no reduction in their half-wave potential (measured at J = 3.0 mA cm–2), whereas the Pt/C catalyst showed a 11.9 mV decrease. Our findings revealed that our SD-Pt thin films also exhibited excellent ORR activity, which offers significant potential for their application as high-performance cathode materials in alkaline fuel cells.
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Feb 2025
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[38966]
Abstract: The electron beam for scanning transmission electron microscopy (STEM) provides rich information about the atomic structure and chemical composition of materials from micron to atomic scale. However, the electron probe can also damage the materials of interest, as the high-energy electrons are often focused on very small sample regions. These effects limit the quality of information which can be extracted from experiments on beam-sensitive materials, such as Li-ion battery materials and metal halide perovskites used in solar cell devices. However, with the increasing interest in these materials to address environmental and societal concerns, a detailed understanding of their microstructure and chemical composition at high spatial resolution is needed to improve their performance and stability. For these materials, the correlation between processing and nanoscale structure-property relationships has been difficult to firmly establish. As shown in Fig. 1a-1c, phase change or amorphisation in beam-sensitive materials can be easily caused by a focused electron probe. Fortunately, this problem can be solved through combined scanning electron nano-diffraction (SEND) and energy dispersive X-ray spectroscopy (EDX) with low electron dose conditions, providing nanoscale crystallographic and chemical information from the specimen. However, the signal-to-noise (SNR) of the EDX data is very poor - with just a few counts in any individual scan prohibiting comprehensive materials characterisation (Fig. 1d). To address this, we perform automated SEND-EDX data acquisition under low dose conditions utilising our automated data analysis workflow. By communicating with two different modalities, i.e., Aztec®; Oxford Instruments and MerlinEM; Quantum Detectors, and using our Python-based software, many SEND-EDX data pairs were simultaneously acquired from a metal halide perovskite. The radially flattened diffraction datasets were then be segmented into distinct phases by using an unsupervised learning approach, non-negative matrix factorisation, and the EDX spectra from identical phases classified earlier were summed across all datasets to enable chemical identification with a much higher SNR than one EDX spectrum image (Fig. 1d) as shown in Fig. 2. In this way we can determine the chemical and crystallographic structure of small phase domains in a highly beam-sensitive multi-phase metal halide perovskite. This research will both demonstrate a novel multi-modal, data-fusion based approach to imaging beam-sensitive materials and shed light on the processing and structure-property relationships of these materials on the nanometre length scale to improve their long-term operational stability.
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Feb 2025
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I09-Surface and Interface Structural Analysis
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Diamond Proposal Number(s):
[36180]
Abstract: MAX phases are a large and growing family of transition metal-based ternary carbides and (carbo)nitrides, that have also attracted significant attention as precursors for a class of two-dimensional materials referred to as MXenes. The ability to partially substitute elements on the M-, A-, and X-sites of the layered crystal structure has expanded MAX phases to over 340 members known to date. They can be exfoliated to form single- and few-layer MXene sheets by removal of the A-element while maintaining the M- and X-elements of the precursor MAX phase. MXenes are extremely interesting materials with properties that are, among other factors, dependent on their chemical composition and offer a wide array of potential applications, for example for energy conversion. Here, we synthesize hitherto unknown solid solution MAX phases, (V1–yMoy)2AlC (y = 0.0–0.5) and exfoliate all compounds with varying V/Mo ratios into the respective MXenes by hydrothermal treatment with in situ-formed hydrofluoric acid. The delaminated MXenes can be utilized for electrocatalytic reactions, here demonstrated for the hydrogen evolution reaction (HER). As the Mo content within the MXenes increases, electrocatalytic activity for HER improves, peaking at an overpotential of 394 mV at 10 mA cm–2 and a Tafel slope of 129 mV dec–1 for (V0.5Mo0.5)2CTx.
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Jan 2025
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I07-Surface & interface diffraction
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Diamond Proposal Number(s):
[32266]
Abstract: Organic solar cells (OSCs) are attracting significant attention due to their low cost, lightweight, and flexible nature. The introduction of nonfullerene acceptors (NFAs) has propelled OSC development into a transformative era. However, the limited availability of wide band gap polymer donors for NFAs poses a critical challenge, hindering further advancements. This study examines the role of developed wide band gap halogenated pyrrolo[3,4-c]pyrrole-1,3(2H,5H)-dione (PPD)-based polymers, in combination with the Y6 nonfullerene acceptor, in bulk heterojunction (BHJ) OSCs. We first focus on the electronic and absorbance modifications brought about by halogen substitution in PPD-based polymers, revealing how these adjustments influence the HOMO/LUMO energy levels and, subsequently, photovoltaic performance. Despite the increased Voc of halogenated polymers due to the optimal band alignment, power conversion efficiencies (PCEs) were decreased due to suboptimal blend morphologies. We second implemented PPD as a solid additive to PM6:Y6, forming ternary OSCs and further improving the PCE. The study provides a nuanced understanding of the interplay between molecular design, device morphology, and OSC performance and opens insights for future research to achieve an optimal balance between band alignment and favorable blend morphology for high-efficiency OSCs.
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Jan 2025
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