B18-Core EXAFS
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Diamond Proposal Number(s):
[42455]
Open Access
Abstract: The direct synthesis of amorphous metal–organic frameworks (aMOFs) is an appealing yet often avoided approach due to the perceived unpredictability of amorphous network formation. Here, we develop a strategy for aMOF synthesis using pre-formed nanoclusters and rigid organic linkers, providing enhanced control over disorder and defect chemistry while bypassing the traditional crystallise–amorphise approach. By systematically comparing this approach to other direct synthesis routes and using X-ray pair distribution function, thermogravimetric, and statistical analyses, we establish key design principles governing aMOF formation. We demonstrate that kinetic control—fast reactions under basic conditions at room temperature—suppresses crystallisation and drives amorphous network formation. The nanocluster approach consistently yields highly disordered frameworks with the shortest coherence lengths among direct synthesis methods. Additionally, we show that tuning metal composition through doping with kinetically inert cations restricts coordination reversibility, significantly increasing defect density and structural disorder. Structural analysis reveals that while aMOFs share motifs with crystalline polymorphs, they cannot be directly mapped onto known structures, highlighting the importance of more nuanced characterisation approaches. By developing a systematic approach to aMOF design, this work provides a foundation for tailoring structural disorder, expanding their potential for catalysis, adsorption, and transport applications.
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Apr 2026
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B18-Core EXAFS
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Diamond Proposal Number(s):
[36175]
Open Access
Abstract: Palladium-loaded phosphine polymers have been designed and used as solid molecular catalysts (SMCs) in telomerization reactions with isoprene and short alcohols. A novel tris-(2-methoxyphenyl)phosphine-based polymer (pTOMPP), previously reported poly triphenylphosphine (pTPP) as well as TPP-based polymers with trigonal and tetragonal linkers were tested either pre-loaded or in-situ-loaded. The novel polymer pTOMPP proved to be an excellent support material during in-situ-loading, outperforming triphenylphosphine based polymers. Surprisingly pre-loaded SMCs resulted in significantly lower activity. XAS studies reveal that the enhanced activity of Pd/pTOMPP is due to the coordination sphere of Pd on the polymer showing a higher contribution of Pd-P bonds forming, whereas XAS spectra of Pd/pTPP show a higher contribution of inactive Pd-acac bonds. Especially pre-loaded polymers show little Pd-P interactions.
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Apr 2026
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Shan
Dai
,
Xiangdi
Zeng
,
Benjamin J.
Moore
,
Yuxiang
Zhu
,
Yuhang
Yang
,
Zi
Wang
,
Luyan
Li
,
Te
Wang
,
Ivan
Da Silva
,
Luke
Keenan
,
Floriana
Tuna
,
Daniel
Lee
,
Sarah
Day
,
Lucy
Saunders
,
Martin
Schroeder
,
Sihai
Yang
Abstract: Metal–organic framework (MOF) materials share some common features with metalloenzymes including site-isolated metal centers that template dynamic substrate activation within a functionalized cavity or pocket. We report the light-induced reversible binding of CO2 in a cerium-based MOF, Ce-UiO-66-NH2, incorporating an amino functionalized linker, which enables photoreduction of CO2 to CO in H2O without using sacrificial agents. A production rate for CO of 126 μmol·g–1·h–1 with 100% selectivity is observed, outperforming its non-amine analogue (Ce-UiO-66) and benchmark catalysts reported to date. In situ infrared, X-ray absorption, electron paramagnetic resonance and transient absorption spectroscopy reveal that photoexcitation induces a ligand-to-metal charge transfer to generate transient open Ce(III) sites that bind CO2 in a μ-(η1-O)(η1-C) binding mode. This binding is reversible and activates CO2 for subsequent photoreduction to CO. This work will promote the design of photocatalysts capable of synthesizing fuels from CO2.
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Mar 2026
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B18-Core EXAFS
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Diamond Proposal Number(s):
[33569]
Open Access
Abstract: Green hydrogen production is limited by the thermodynamic energy requirement of water splitting. By decoupling the anodic and cathodic reactions using redox mediators, alternative feedstocks such as lignocellulosic biomass can yield comparable hydrogen purity with around half the total electrical energy input of conventional water electrolysis. Keggin-type heteropolyacids such as phosphomolybdic acid (H3PMo12O40) are increasingly of interest as mediators in decoupled electrochemical energy conversion applications, due to their reversible redox characteristics. However, the redox behaviour of heteropolyacids in aqueous solution during this process is still poorly understood. X-ray absorption spectroscopy (XAS) techniques offer the opportunity to directly probe changes in oxidation state and local structure of the mediator in-operando, allowing unprecedented insight into redox processes in a flow cell environment. Here, for the first time, we demonstrate operando XAS of reduced phosphomolybdic acid as it undergoes oxidation in a proton exchange membrane electrolyser with bespoke 3D-printed flow-fields. Changes in the time-resolved XAS were correlated to structural changes in the Keggin anion, which were closely related to the state-of-charge of the mediator, laying the groundwork for future studies of solution-phase Keggin-type heteropolyacid redox states. Furthermore, reduction of the phosphomolybdic acid via mild thermal digestion of either pure lignin or real agricultural biowaste is compared, in a step towards real-world applications. This work contributes significantly to the efficient and low-cost production of green hydrogen from waste biomass feedstocks, as well as providing insights into similar decoupled electrolysis processes.
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Jan 2026
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B18-Core EXAFS
E01-JEM ARM 200CF
I09-Surface and Interface Structural Analysis
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Thomas J.
Liddy
,
Benjamin J.
Young
,
Emerson C.
Kohlrausch
,
Andreas
Weilhard
,
Gazi N.
Aliev
,
Yifan
Chen
,
Manfred E.
Schuster
,
Mohsen
Danaie
,
Luke L.
Keenan
,
Donato
Decarolis
,
Diego
Gianolio
,
Siqi
Wang
,
Mingming
Zhu
,
Graham J.
Hutchings
,
David M.
Grant
,
Wolfgang
Theis
,
Tien-Lin
Lee
,
David A.
Duncan
,
Alberto
Roldan
,
Andrei N.
Khlobystov
,
Jesum
Alves Fernandes
Diamond Proposal Number(s):
[38764]
Open Access
Abstract: Ammonia is an attractive hydrogen carrier, yet its practical use is limited by the need for efficient catalytic decomposition. We demonstrate that in-situ N-doping of Ru nanoparticles and graphitized carbon nanofiber supports during reaction produces a sharp increase in hydrogen production during the first 40 h, followed by stable activity. Spectroscopic and microscopic analyses, together with density functional theory simulations, reveal that Ru nitridation is rapid and support-independent, resulting in a mechanistic shift from the traditional Langmuir–Hinshelwood to a Mars–van Krevelen pathway, further confirmed by isotopic labelling experiments. In contrast, the progressive nitridation of the carbon support, observed via X-ray photoelectron spectroscopy, modulates the electronic environment of Ru and functions as a dynamic nitrogen reservoir that enables reversible N atoms exchange with the Ru particles, facilitating N desorption from the Ru surface and thereby governing the catalytic activity enhancement. These new findings provide new mechanistic insight into ammonia decomposition and establish progressive nitrogen doping of carbon supports as a strategy for designing efficient metal-based catalysts for hydrogen production.
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Dec 2025
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B18-Core EXAFS
I20-EDE-Energy Dispersive EXAFS (EDE)
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Wenyuan
Huang
,
Bing
An
,
Zeyu
Chen
,
Yu
Han
,
Yinlin
Chen
,
Jiangnan
Li
,
Xue
Han
,
Shaojun
Xu
,
Danielle
Crawshaw
,
Evan
Tillotson
,
Sarah J.
Haigh
,
Bing
Han
,
Christopher M. A.
Parlett
,
Luke
Keenan
,
Svemir
Rudic
,
Yongqiang
Cheng
,
Ben F.
Spencer
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[28575, 31729]
Open Access
Abstract: The development of earth-abundant metal-based catalysts is an important goal for the synthesis of fine chemicals. Here, an active nickel catalyst supported on a robust metal–organic framework, MFM-300(Cr), is reported which shows an exceptional performance for reductive amination, a reaction that has long been dominated by noble metals. Ni/MFM-300(Cr) promotes the synthesis of 38 primary amines via reductive amination of their parent carbonyl compounds, including biomass-derived aldehydes and ketones, using NH3 in the presence of H2 operating under relatively mild conditions (5 bar and 160 °C). X-ray absorption spectroscopy confirms the formation of mixtures of metallic Ni0 and Nin+ active sites, while in situ inelastic neutron scattering, coupled with modeling, reveals details of the mechanism of catalysis involving the formation of N-benzyl-1-phenylmethanediamine (BPDI) as an intermediate species in the generation of benzylamine. Cooperativity between Ni sites and MFM-300(Cr) creates an optimal microenvironment for the efficient activation of carbonyl compounds and the selective production of primary amines using a non-precious metal-based catalyst.
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Oct 2025
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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-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
E01-JEM ARM 200CF
E02-JEM ARM 300CF
I20-EDE-Energy Dispersive EXAFS (EDE)
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Lu
Chen
,
Xuze
Guan
,
Zhaofu
Fei
,
Hiroyuki
Asakura
,
Lun
Zhang
,
Zhipeng
Wang
,
Xinlian
Su
,
Zhangyi
Yao
,
Luke L.
Keenan
,
Shusaku
Hayama
,
Matthijs A.
Van Spronsen
,
Burcu
Karagoz
,
Georg
Held
,
Christopher S.
Allen
,
David G.
Hopkinson
,
Donato
Decarolis
,
June
Callison
,
Paul J.
Dyson
,
Feng Ryan
Wang
Diamond Proposal Number(s):
[30622, 33257, 31922]
Open Access
Abstract: Selective catalytic oxidation (SCO) of NH3 to N2 is one of the most effective methods used to eliminate NH3 emissions. However, achieving high conversion over a wide operating temperature range while avoiding over-oxidation to NOx remains a significant challenge. Here, we report a bi-metallic surficial catalyst (PtSCuO/Al2O3) with improved Pt atom efficiency that overcomes the limitations of current catalysts. It achieves full NH3 conversion at 250 °C with a weight hourly space velocity of 600 ml NH3·h−1·g−1, which is 50 °C lower than commercial Pt/Al2O3, and maintains high N2 selectivity through a wide temperature window. Operando XAFS studies reveal that the surface Pt atoms in PtSCuO/Al2O3 enhance the redox properties of the Cu species, thus accelerating the Cu2+ reduction rate and improving the rate of the NH3-SCO reaction. Moreover, a synergistic effect between Pt and Cu sites in PtSCuO/Al2O3 contributes to the high selectivity by facilitating internal selective catalytic reduction.
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Jan 2025
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Xu
Chen
,
Dhruv
Menon
,
Xiaoliang
Wang
,
Meng
He
,
Mohammad Reza
Alizadeh Kiapi
,
Mehrdad
Asgari
,
Yuexi
Lyu
,
Xianhui
Tang
,
Luke L.
Keenan
,
William
Shepard
,
Lik H.
Wee
,
Sihai
Yang
,
Omar K.
Farha
,
David
Fairen-Jimenez
Diamond Proposal Number(s):
[32566, 34552]
Open Access
Abstract: Selective CO2 capture from industry is crucial for reducing emissions from fossil fuel combustion. Flexible metal-organic frameworks (MOFs) have shown promise for CO2 adsorption via differential binding and size-exclusion mechanisms. However, achieving precise pore-size control to selectively capture CO2, particularly in the presence of N2 and water, remains a challenge. Here, we demonstrate a strategy for frustrating framework flexibility in a MOF to create an optimal, confined pore environment that enhances selective CO2 recognition while maintaining high working capacity. We designed a flexible MOF, Cambridge University (CU)-4, by using a bulky cubane-derived ligand and In3+ ions that undergo dynamic breathing with a 2 Å contraction upon solvent exchange and removal. In situ synchrotron X-ray diffraction and molecular simulations reveal that the stable narrow-pore configuration creates a hydrogen-rich cavity that selectively binds CO2 via multiple hydrogen bonds. This physisorption-based CO2 recognition remains effective even at 80% humidity, making CU-4 promising for post-combustion carbon capture.
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Jan 2025
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Fangfang
Peng
,
Bin
Zhang
,
Runyao
Zhao
,
Shiqiang
Liu
,
Yuxuan
Wu
,
Shaojun
Xu
,
Luke L.
Keenan
,
Huizhen
Liu
,
Qingli
Qian
,
Tianbin
Wu
,
Haijun
Yang
,
Zhimin
Liu
,
Jikun
Li
,
Bingfeng
Chen
,
Xinchen
Kang
,
Buxing
Han
Open Access
Abstract: Selective hydrogenolysis of biomass-derived furanic compounds is a promising approach for synthesizing aliphatic polyols by opening the furan ring. However, there remains a significant need for highly efficient catalysts that selectively target the Csp2–O bond in the furan ring, as well as for a deeper understanding of the fundamental atomistic mechanisms behind these reactions. In this study, we present the use of Pt–Fe bimetallic catalysts supported on layered double hydroxides [PtFex/LDH] for the hydrogenolysis of furanic compounds into aliphatic alcohols, achieving over 90% selectivity toward diols and triols. Our findings reveal that the synergy between Pt nanoparticles, atomically dispersed Pt sites and the support facilitates the formation of hydride-proton pair at the Ptδ+⋯O2− Lewis acid–base unit of PtFex/LDH through hydrogen spillover. The hydride specifically targets the Csp2–O bond in the furan ring, initiating an SN2 reaction and ring cleavage. Moreover, the presence of Fe improves the yield of desired alcohols by inhibiting the adsorption of vinyl groups, thereby suppressing the hydrogenation of the furan ring.
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Nov 2024
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