E02-JEM ARM 300CF
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Wendong
Wang
,
Gareth R.
Tainton
,
Nicholas J.
Clark
,
James G.
Mchugh
,
Xue
Li
,
Sam
Sullivan-Allsop
,
David G.
Hopkinson
,
Oldrich
Cicvárek
,
Francisco
Selles
,
Rui
Zhang
,
Joshua D.
Swindell
,
Alex
Summerfield
,
David J.
Lewis
,
Vladimir I.
Fal'Ko
,
Zdenek
Sofer
,
Sarah
Haigh
,
Roman
Gorbachev
Diamond Proposal Number(s):
[39088]
Abstract: Transition metal diiodides such as FeI2, NiI2, and CoI2 are an emerging class of 2D magnets exhibiting rich and diverse magnetic behavior, but their study at the monolayer limit has been severely hindered by fabrication challenges due to their air-sensitivity. Here, we introduce a polymer-free method for clean, rapid, and high-yield assembly of hermetically encapsulated suspended samples of air-sensitive monolayers. Applied to diiodides, it enables atomic resolution characterization of thin samples down to the monolayer limit using transmission electron microscopy. Our imaging, combined with complementary first-principles calculations, reveals an unusually small energy barrier between alternate stable stacking polytypes in few-layer films, enabling extrinsic control of the stacking phase. We also observe stable isolated iodine vacancies that do not aggregate to form extended structures and identify and verify the stability of the various edge configurations of thin samples. These results establish the structural characteristics of these materials in the thin limit and more broadly demonstrate the utility of our transfer platform for creating atomically clean suspended van der Waals heterostructures.
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Jan 2026
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E02-JEM ARM 300CF
I09-Surface and Interface Structural Analysis
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Benedikt P.
Klein
,
Matthew A.
Stoodley
,
Joel
Deyerling
,
Luke A.
Rochford
,
Dylan B.
Morgan
,
David G.
Hopkinson
,
Sam
Sullivan-Allsop
,
Henry
Thake
,
Fulden
Eratam
,
Lars
Sattler
,
Sebastian M.
Weber
,
Gerhard
Hilt
,
Alexander
Generalov
,
Alexei
Preobrajenski
,
Thomas
Liddy
,
Leon B. S.
Williams
,
Mhairi A.
Buchan
,
Graham A
Rance
,
Tien-Lin
Lee
,
Alex
Saywell
,
Roman
Gorbachev
,
Sarah J.
Haigh
,
Christopher S.
Allen
,
Willi
Auwärter
,
Reinhard
Maurer
,
David A.
Duncan
Diamond Proposal Number(s):
[25379, 30875, 31695, 31165, 33709]
Open Access
Abstract: Chemical vapour deposition enables large-domain growth of ideal graphene, yet many applications of graphene require the controlled inclusion of specific defects. We present a one-step chemical vapour deposition procedure aimed at retaining the precursor topology when incorporated into the grown carbonaceous film. When azupyrene, the molecular analogue of the Stone–Wales defect in graphene, is used as a precursor, carbonaceous monolayers with a range of morphologies are produced as a function of the copper substrate growth temperature. The higher the substrate temperature during deposition, the closer the resulting monolayer is to ideal graphene. Analysis, with a set of complementary materials characterisation techniques, reveals morphological changes closely correlated with changes in the atomic adsorption heights, network topology, and concentration of 5-/7-membered carbon rings. The engineered defective carbon monolayers can be transferred to different substrates, potentially enabling applications in nanoelectronics, sensorics, and catalysis.
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Sep 2025
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B18-Core EXAFS
B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Zhaodong
Zhu
,
Mengtian
Fan
,
Meng
He
,
Bing
An
,
Yinlin
Chen
,
Shaojun
Xu
,
Tianze
Zhou
,
Alena M.
Sheveleva
,
Meredydd
Kippax-Jones
,
Lutong
Shan
,
Yongqiang
Chen
,
Hamish
Cavaye
,
Jeff
Armstrong
,
Svemir
Rudic
,
Stewart F.
Parker
,
William
Thornley
,
Evan
Tillotson
,
Matthew
Lindley
,
Shenglong
Tian
,
Daniel
Lee
,
Shiyu
Fu
,
Mark D.
Frogley
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Sarah J.
Haigh
,
Sihai
Yang
Abstract: The methanol-to-olefins (MTO) process has the potential to bridge future gaps in the supply of sustainable lower olefins. Promoting the selectivity of propylene and ethylene and revealing the catalytic role of active sites are challenging goals in MTO reactions. Here, we report a novel heteroatomic silicoaluminophosphate (SAPO) zeolite, SAPO-34-Ta, which incorporates active tantalum(V) sites within the framework to afford an optimal distribution of acidity. SAPO-34-Ta exhibits a remarkable total selectivity of 85.8% for propylene and ethylene with a high selectivity of 54.9% for propylene on full conversion of methanol at 400 oC. In situ and operando synchrotron powder X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy and inelastic neutron scattering, coupled with theoretical calculations, reveal trimethyloxonium as the key reaction intermediate, promoting the formation of first carbon-carbon bonds in olefins. The tacit cooperation between tantalum(V) and Brønsted acid sites within SAPO-34 provides an efficient platform for selective production of lower olefins from methanol.
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Jan 2025
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Wenyaun
Huang
,
Qingqing
Mei
,
Shaojun
Xu
,
Bing
An
,
Meng
He
,
Jiangnan
Li
,
Yinlin
Chen
,
Xue
Han
,
Tian
Luo
,
Lixia
Guo
,
Joseph
Hurd
,
Daniel
Lee
,
Evan
Tillotson
,
Sarah
Haigh
,
Alex
Walton
,
Sarah
Day
,
Louise S.
Natrjan
,
Martin
Schroeder
,
Sihai
Yang
Open Access
Abstract: Formamides are important feedstocks for the manufacture of many fine chemicals. State-of-the-art synthesis of formamides relies on the use of an excess amount of reagents, giving copious waste and thus poor atom-economy. Here, we report the first example of direct synthesis of N-formamides by coupling two challenging reactions, namely reductive amination of carbonyl compounds, particularly biomass-derived aldehydes and ketones, and fixation of CO2 in the presence of H2 over a metal-organic framework supported ruthenium catalyst, Ru/MFM-300(Cr). Highly selective production of N-formamides has been observed for a wide range of carbonyl compounds. Synchrotron X-ray powder diffraction reveals the presence of strong host-guest binding interactions via hydrogen bonding and parallel-displaced π···π interactions between the catalyst and adsorbed substrates facilitating the activation of substrates and promoting selectivity to formamides. The use of multifunctional porous catalysts to integrate CO2 utilisation in the synthesis of formamide products will have a significant impact in the sustainable synthesis of feedstock chemicals.
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Oct 2023
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B18-Core EXAFS
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Yujie
Ma
,
Xue
Han
,
Shaojun
Xu
,
Zhe
Li
,
Wanpeng
Lu
,
Bing
An
,
Daniel
Lee
,
Sarayute
Chansai
,
Alena M.
Sheveleva
,
Zi
Wang
,
Yinlin
Chen
,
Jiangnan
Li
,
Weiyao
Li
,
Rongsheng
Cai
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Lewis
Hughes
,
Pascal
Manuel
,
Anibal J.
Ramirez-Cuesta
,
Sarah J.
Haigh
,
Christopher
Hardacre
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[19850]
Open Access
Abstract: Conversion of methane (CH4) to ethylene (C2H4) and/or acetylene (C2H2) enables routes to a wide range of products directly from natural gas. However, high reaction temperatures and pressures are often required to activate and convert CH4 controllably, and separating C2+ products from unreacted CH4 can be challenging. Here, we report the direct conversion of CH4 to C2H4 and C2H2 driven by non-thermal plasma under ambient (25 °C and 1 atm) and flow conditions over a metal–organic framework material, MFM-300(Fe). The selectivity for the formation of C2H4 and C2H2 reaches 96% with a high time yield of 334 μmol gcat–1 h–1. At a conversion of 10%, the selectivity to C2+ hydrocarbons and time yield exceed 98% and 2056 μmol gcat–1 h–1, respectively, representing a new benchmark for conversion of CH4. In situ neutron powder diffraction, inelastic neutron scattering and solid-state nuclear magnetic resonance, electron paramagnetic resonance (EPR), and diffuse reflectance infrared Fourier transform spectroscopies, coupled with modeling studies, reveal the crucial role of Fe–O(H)–Fe sites in activating CH4 and stabilizing reaction intermediates via the formation of an Fe–O(CH3)–Fe adduct. In addition, a cascade fixed-bed system has been developed to achieve online separation of C2H4 and C2H2 from unreacted CH4 for direct use. Integrating the processes of CH4 activation, conversion, and product separation within one system opens a new avenue for natural gas utility, bridging the gap between fundamental studies and practical applications in this area.
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Sep 2023
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E01-JEM ARM 200CF
I20-EDE-Energy Dispersive EXAFS (EDE)
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Hui
Luo
,
Victor Y.
Yukuhiro
,
Pablo S.
Fernández
,
Jingyu
Feng
,
Paul
Thompson
,
Reshma R.
Rao
,
Rongsheng
Cai
,
Silvia
Favero
,
Sarah J.
Haigh
,
James R.
Durrant
,
Ifan E. L.
Stephens
,
Maria-Magdalena
Titirici
Diamond Proposal Number(s):
[28663, 25476]
Open Access
Abstract: Pt-based bimetallic electrocatalysts are promising candidates to convert surplus glycerol from the biodiesel industry to value-added chemicals and coproduce hydrogen. It is expected that the nature and content of the elements in the bimetallic catalyst can not only affect the reaction kinetics but also influence the product selectivity, providing a way to increase the yield of the desired products. Hence, in this work, we investigate the electrochemical oxidation of glycerol on a series of PtNi nanoparticles with increasing Ni content using a combination of physicochemical structural analysis, electrochemical measurements, operando spectroscopic techniques, and advanced product characterizations. With a moderate Ni content and a homogenously alloyed bimetallic Pt–Ni structure, the PtNi2 catalyst displayed the highest reaction activity among all materials studied in this work. In situ FTIR data show that PtNi2 can activate the glycerol molecule at a more negative potential (0.4 VRHE) than the other PtNi catalysts. In addition, its surface can effectively catalyze the complete C–C bond cleavage, resulting in lower CO poisoning and higher stability. Operando X-ray absorption spectroscopy and UV–vis spectroscopy suggest that glycerol adsorbs strongly onto surface Ni(OH)x sites, preventing their oxidation and activation of oxygen or hydroxyl from water. As such, we propose that the role of Ni in PtNi toward glycerol oxidation is to tailor the electronic structure of the pure Pt sites rather than a bifunctional mechanism. Our experiments provide guidance for the development of bimetallic catalysts toward highly efficient, selective, and stable glycerol oxidation reactions.
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Nov 2022
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I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
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Elizabeth L.
Bell
,
Ross
Smithson
,
Siobhan
Kilbride
,
Jake
Foster
,
Florence J.
Hardy
,
Saranarayanan
Ramachandran
,
Aleksander A.
Tedstone
,
Sarah J.
Haigh
,
Arthur A.
Garforth
,
Philip J. R.
Day
,
Colin
Levy
,
Michael P.
Shaver
,
Anthony P.
Green
Diamond Proposal Number(s):
[12788, 17773]
Abstract: The recent discovery of IsPETase, a hydrolytic enzyme that can deconstruct poly(ethylene terephthalate) (PET), has sparked great interest in biocatalytic approaches to recycle plastics. Realization of commercial use will require the development of robust engineered enzymes that meet the demands of industrial processes. Although rationally engineered PETases have been described, enzymes that have been experimentally optimized via directed evolution have not previously been reported. Here, we describe an automated, high-throughput directed evolution platform for engineering polymer degrading enzymes. Applying catalytic activity at elevated temperatures as a primary selection pressure, a thermostable IsPETase variant (HotPETase, Tm = 82.5 °C) was engineered that can operate at the glass transition temperature of PET. HotPETase can depolymerize semicrystalline PET more rapidly than previously reported PETases and can selectively deconstruct the PET component of a laminated multimaterial. Structural analysis of HotPETase reveals interesting features that have emerged to improve thermotolerance and catalytic performance. Our study establishes laboratory evolution as a platform for engineering useful plastic degrading enzymes.
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Aug 2022
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B18-Core EXAFS
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Chris
Foster
,
Samuel
Shaw
,
Thomas
Neill
,
Nick
Bryan
,
Nick
Sherriff
,
Louise S.
Natrajan
,
Hannah
Wilson
,
Laura
Lopez-Odriozola
,
Bruce
Rigby
,
Sarah J.
Haigh
,
Yi-Chao
Zou
,
Robert
Harrison
,
Katherine
Morris
Diamond Proposal Number(s):
[17243, 21441]
Open Access
Abstract: In the United Kingdom, decommissioning of legacy spent fuel storage facilities involves the retrieval of radioactive sludges that have formed as a result of corrosion of Magnox nuclear fuel. Retrieval of sludges may re-suspend a colloidal fraction of the sludge, thereby potentially enhancing the mobility of radionuclides including uranium. The colloidal properties of the layered double hydroxide (LDH) phase hydrotalcite, a key product of Magnox fuel corrosion, and its interactions with U(VI) are of interest. This is because colloidal hydrotalcite is a potential transport vector for U(VI) under the neutral-to-alkaline conditions characteristic of the legacy storage facilities and other nuclear decommissioning scenarios. Here, a multi-technique approach was used to investigate the colloidal stability of hydrotalcite and the U(VI) sorption mechanism(s) across pH 7–11.5 and with variable U(VI) surface loadings (0.01–1 wt %). Overall, hydrotalcite was found to form stable colloidal suspensions between pH 7 and 11.5, with some evidence for Mg2+ leaching from hydrotalcite colloids at pH ≤ 9. For systems with U present, >98% of U(VI) was removed from the solution in the presence of hydrotalcite, regardless of pH and U loading, although the sorption mode was affected by both pH and U concentrations. Under alkaline conditions, U(VI) surface precipitates formed on the colloidal hydrotalcite nanoparticle surface. Under more circumneutral conditions, Mg2+ leaching from hydrotalcite and more facile exchange of interlayer carbonate with the surrounding solution led to the formation of uranyl carbonate species (e.g., Mg(UO2(CO3)3)2–(aq)). Both X-ray absorption spectroscopy (XAS) and luminescence analysis confirmed that these negatively charged species sorbed as both outer- and inner-sphere tertiary complexes on the hydrotalcite surface. These results demonstrate that hydrotalcite can form pseudo-colloids with U(VI) under a wide range of pH conditions and have clear implications for understanding the uranium behavior in environments where hydrotalcite and other LDHs may be present.
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Feb 2022
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E01-JEM ARM 200CF
|
Diamond Proposal Number(s):
[26559]
Open Access
Abstract: State of the art electrocatalysts for the hydrogen evolution reaction (HER) are based on metal nanoparticles (NPs). It has been shown that the localized surface plasmon resonance (LSPR) excitation in plasmonic NPs can be harvested to accelerate a variety of molecular transformations. This enables the utilization of visible light as an energy input to enhance HER performances. However, most metals that are active toward the HER do not support LSPR excitation in the visible or near-IR ranges. We describe herein the synthesis of gold–rhodium core–shell nanoflowers (Au@Rh NFs) that are composed of a core made up of spherical Au NPs and shells containing Rh branches. The Au@Rh NFs were employed as a model system to probe how the LSPR excitation from Au NPs can lead to an enhancement in the HER performance for Rh. Our data demonstrate that the LSPR excitation at 533 nm (and 405 nm) leads to an improvement in the HER performance of Rh, which depends on the morphological features of the Au@Rh NFs, offering opportunities for optimization of the catalytic performance. Control experiments indicate that this improvement originates from the stronger interaction of Au@Rh NFs with H2O molecules at the surface, leading to an icelike configuration, which facilitated the HER under LSPR excitation.
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Oct 2021
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E02-JEM ARM 300CF
|
Yi-Chao
Zou
,
Lucas
Mogg
,
Nick
Clark
,
Cihan
Bacaksiz
,
Slavisa
Milanovic
,
Vishnu
Sreepal
,
Guang-Ping
Hao
,
Yi-Chi
Wang
,
David G.
Hopkinson
,
Roman
Gorbachev
,
Samuel
Shaw
,
Kostya S.
Novoselov
,
Rahul
Raveendran-Nair
,
Francois M.
Peeters
,
Marcelo
Lozada-Hidalgo
,
Sarah
Haigh
Diamond Proposal Number(s):
[21981, 21597]
Abstract: The physical properties of clays and micas can be controlled by exchanging ions in the crystal lattice. Atomically thin materials can have superior properties in a range of membrane applications, yet the ion-exchange process itself remains largely unexplored in few-layer crystals. Here we use atomic-resolution scanning transmission electron microscopy to study the dynamics of ion exchange and reveal individual ion binding sites in atomically thin and artificially restacked clays and micas. We find that the ion diffusion coefficient for the interlayer space of atomically thin samples is up to 104 times larger than in bulk crystals and approaches its value in free water. Samples where no bulk exchange is expected display fast exchange at restacked interfaces, where the exchanged ions arrange in islands with dimensions controlled by the moiré superlattice dimensions. We attribute the fast ion diffusion to enhanced interlayer expandability resulting from weaker interlayer binding forces in both atomically thin and restacked materials. This work provides atomic scale insights into ion diffusion in highly confined spaces and suggests strategies to design exfoliated clay membranes with enhanced performance.
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Aug 2021
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