I11-High Resolution Powder Diffraction
I20-EDE-Energy Dispersive EXAFS (EDE)
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Longfei
Lin
,
Mengtian
Fan
,
Alena M.
Sheveleva
,
Xue
Han
,
Zhimou
Tang
,
Joseph H.
Carter
,
Ivan
Da Silva
,
Christopher
Parlett
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
German
Sastre
,
Svemir
Rudic
,
Hamish
Cavaye
,
Stewart F.
Parker
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Anibal J.
Ramirez-Cuesta
,
Martin P.
Attfield
,
Yueming
Liu
,
Chiu C.
Tang
,
Buxing
Han
,
Sihai
Yang
Diamond Proposal Number(s):
[2359]
Open Access
Abstract: Optimising the balance between propene selectivity, propene/ethene ratio and catalytic stability and unravelling the explicit mechanism on formation of the first carbon–carbon bond are challenging goals of great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control the nature of active sites within the pores of commercial MFI-zeolites by incorporating tantalum(V) and aluminium(III) centres into the framework. The resultant TaAlS-1 zeolite exhibits simultaneously remarkable propene selectivity (51%), propene/ethene ratio (8.3) and catalytic stability (>50 h) at full methanol conversion. In situ synchrotron X-ray powder diffraction, X-ray absorption spectroscopy and inelastic neutron scattering coupled with DFT calculations reveal that the first carbon–carbon bond is formed between an activated methanol molecule and a trimethyloxonium intermediate. The unprecedented cooperativity between tantalum(V) and Brønsted acid sites creates an optimal microenvironment for efficient conversion of methanol and thus greatly promotes the application of zeolites in the sustainable manufacturing of light olefins.
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Feb 2021
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B22-Multimode InfraRed imaging And Microspectroscopy
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Jiangnan
Li
,
Zhengyang
Zhou
,
Xue
Han
,
Xinran
Zhang
,
Yong
Yan
,
Weiyao
Li
,
Gemma L.
Smith
,
Yongqiang
Cheng
,
Laura J.
Mcormick Mpherson
,
Simon J.
Teat
,
Mark D.
Frogley
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Alexander J.
Blake
,
Junliang
Sun
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[22137]
Abstract: Structural transitions of host systems in response to guest binding dominate many chemical processes. We report an unprecedented type of structural flexibility within a meta-rigid material, MFM-520, which exhibits a reversible periodic-to-aperiodic structural transition resulting from a drastic distortion of a [ZnO4N] node controlled by the specific host–guest interactions. The aperiodic crystal structure of MFM-520 has no three-dimensional (3D) lattice periodicity but shows translational symmetry in higher-dimensional (3 + 2)D space. We have directly visualized the aperiodic state which is induced by incommensurate modulation of the periodic framework of MFM-520·H2O upon dehydration to give MFM-520. Filling MFM-520 with CO2 and SO2 reveals that, while CO2 has a minimal structural influence, SO2 can further modulate the structure incommensurately. MFM-520 shows exceptional selectivity for SO2 under flue-gas desulfurization conditions, and the facile release of captured SO2 from MFM-520 enabled the conversion to valuable sulfonamide products. MFM-520 can thus be used as a highly efficient capture and delivery system for SO2.
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Oct 2020
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B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Xiaolin
Li
,
Juehua
Wang
,
Xinran
Zhang
,
Xue
Han
,
Ivan
Da Silva
,
Christopher G.
Morris
,
Shaojun
Xu
,
Damian M.
Wilary
,
Yinyong
Sun
,
Yongqiang
Cheng
,
Claire A.
Murray
,
Chiu C.
Tang
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Tristan
Lowe
,
Haifei
Zhang
,
Anibal J.
Ramirez-cuesta
,
K. Mark
Thomas
,
Leslie W.
Bolton
,
Sihai
Yang
,
Martin
Schroeder
,
Nannan
Bai
Diamond Proposal Number(s):
[13247]
Open Access
Abstract: The demand for xylenes is projected to increase over the coming decades. The separation of xylene isomers, particularly p- and m-xylenes, is vital for the production of numerous polymers and materials. However, current state-of-the-art separation is based upon fractional crystallisation at 220 K which is highly energy intensive. Here, we report the discrimination of xylene isomers via refinement of the pore size in a series of porous metal–organic frameworks, MFM-300, at sub-angstrom precision leading to the optimal kinetic separation of all three xylene isomers at room temperature. The exceptional performance of MFM-300 for xylene separation is confirmed by dynamic ternary breakthrough experiments. In-depth structural and vibrational investigations using synchrotron X-ray diffraction and terahertz spectroscopy define the underlying host–guest interactions that give rise to the observed selectivity (p-xylene < o-xylene < m-xylene) and separation factors of 4.6–18 for p- and m-xylenes.
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Aug 2020
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B22-Multimode InfraRed imaging And Microspectroscopy
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Thien D.
Duong
,
Sergey A.
Sapchenko
,
Ivan
Da Silva
,
Harry G. W.
Godfrey
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Pascal
Manuel
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Anibal J.
Ramirez-cuesta
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[14938]
Open Access
Abstract: Metal–organic frameworks (MOFs) functionalised with amine, amide and hydroxyl groups show great promise for CO2 binding due to their ability to form hydrogen bonds to CO2. Herein we report the adsorption and selectivity of CO2 in four iso-reticular MOFs adopting the NbO topology. Functionalisation of the parent MOF, MFM-102, with –NO2, –NH2 and alkyl groups leads to an enhancement of CO2 adsorption of up to 36% for the NO2-decorated MOF and with raised selectivity. MFM-102-NO2 shows the highest adsorption capacity for CO2 (184 cm3 g−1 at 273 K and 1.0 bar) within this series, comparable to the best-behaving iso-reticular MOFs. At 298 K and 1.0 bar, MFM-102-NO2 shows a CO2/CH4 selectivity of 5.0. In situ inelastic neutron scattering and synchrotron FT-IR micro-spectroscopy were employed to elucidate the host–guest interaction dynamics within CO2-loaded MFM-102-NO2. Neutron powder diffraction enabled the direct observation of the preferred binding domains in MFM-102-NO2, and, to the best of our knowledge, we report the first example of CO2 binding to a –NO2 group in a porous MOF. Synergistic effects between the –NO2 group and the open metal sites lead to optimal binding of CO2 molecules within MFM-102-NO2 via hydrogen bonding to C–H groups.
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May 2020
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I11-High Resolution Powder Diffraction
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Yuchao
Chai
,
Xue
Han
,
Weiyao
Li
,
Shanshan
Liu
,
Sikai
Yao
,
Chong
Wang
,
Wei
Shi
,
Ivan
Da Silva
,
Pascal
Manuel
,
Yongqiang
Cheng
,
Luke D.
Daemen
,
Anibal J.
Ramirez-cuesta
,
Chiu C.
Tang
,
Ling
Jiang
,
Sihai
Yang
,
Naijia
Guan
,
Landong
Li
Diamond Proposal Number(s):
[23483]
Open Access
Abstract: The efficient removal of alkyne impurities for the production of polymer-grade lower olefins remains an important and challenging goal for many industries. We report a strategy to control the pore interior of faujasite (FAU) zeolites by the confinement of isolated open nickel(II) sites in their six-membered rings. Under ambient conditions, Ni@FAU showed remarkable adsorption of alkynes and efficient separations of acetylene/ethylene, propyne/propylene, and butyne/1,3-butadiene mixtures, with unprecedented dynamic separation selectivities of 100, 92, and 83, respectively. In situ neutron diffraction and inelastic neutron scattering revealed that confined nickel(II) sites enabled chemoselective and reversible binding to acetylene through the formation of metastable [Ni(II)(C2H2)3] complexes. Control of the chemistry of pore interiors of easily scalable zeolites has unlocked their potential in challenging industrial separations.
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May 2020
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Longfei
Lin
,
Alena M.
Sheveleva
,
Ivan
Da Silva
,
Christopher M. A.
Parlett
,
Zhimou
Tang
,
Yueming
Liu
,
Mengtian
Fan
,
Xue
Han
,
Joseph H.
Carter
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Chiu C.
Tang
,
Sihai
Yang
Diamond Proposal Number(s):
[15151, 24726]
Abstract: The efficient production of light olefins from renewable biomass is a vital and challenging target to achieve future sustainable chemical processes. Here we report a hetero-atomic MFI-type zeolite (NbAlS-1), over which aqueous solutions of γ-valerolactone (GVL), obtained from biomass-derived carbohydrates, can be quantitatively converted into butenes with a yield of >99% at ambient pressure under continuous flow conditions. NbAlS-1 incorporates simultaneously niobium(v) and aluminium(iii) centres into the framework and thus has a desirable distribution of Lewis and Brønsted acid sites with optimal strength. Synchrotron X-ray diffraction and absorption spectroscopy show that there is cooperativity between Nb(v) and the Brønsted acid sites on the confined adsorption of GVL, whereas the catalytic mechanism for the conversion of the confined GVL into butenes is revealed by in situ inelastic neutron scattering, coupled with modelling. This study offers a prospect for the sustainable production of butene as a platform chemical for the manufacture of renewable materials.
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Dec 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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Xinchen
Kang
,
Kai
Lyu
,
Lili
Li
,
Jiangnan
Li
,
Louis
Kimberley
,
Bin
Wang
,
Lifei
Liu
,
Yongqiang
Cheng
,
Mark D.
Frogley
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Robert A. W.
Dryfe
,
Buxing
Han
,
Sihai
Yang
,
Martin
Schroder
Diamond Proposal Number(s):
[19171]
Open Access
Abstract: Incorporation of mesopores and active sites into metal-organic framework (MOF) materials to uncover new efficient catalysts is a highly desirable but challenging task. We report the first example of a mesoporous MOF obtained by templated electrosynthesis using an ionic liquid as both electrolyte and template. The mesoporous Cu(II)-MOF MFM-100 has been synthesised in 100 seconds at room temperature, and this material incorporates crystal defects with uncoupled Cu(II) centres as evidenced by confocal fluorescence microscopy and electron paramagnetic resonance spectroscopy. MFM-100 prepared in this way shows exceptional catalytic activity for the aerobic oxidation of alcohols to produce aldehydes in near quantitative yield and selectivity under mild conditions, as well as having excellent stability and reusability over repeated cycles. The catalyst-substrate binding interactions have been probed by inelastic neutron scattering. This study offers a simple strategy to create mesopores and active sites simultaneously via electrochemical formation of crystal defects to promote efficient catalysis using MOFs.
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Oct 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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Gemma L.
Smith
,
Jennifer E.
Eyley
,
Xue
Han
,
Xinran
Zhang
,
Jiangnan
Li
,
Nicholas M.
Jacques
,
Harry G. W.
Godfrey
,
Stephen P.
Argent
,
Laura J.
Mccormick Mcpherson
,
Simon J.
Teat
,
Yongqiang
Cheng
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Sarah
Day
,
Chiu C.
Tang
,
Timothy L.
Easun
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Sihai
Yang
,
Martin
Schroeder
Abstract: Emissions of SO2 from flue gas and marine transport have detrimental impacts on the environment and human health, but SO2 is also an important industrial feedstock if it can be recovered, stored and transported efficiently. Here we report the exceptional adsorption and separation of SO2 in a porous material, [Cu2(L)] (H4L = 4′,4‴-(pyridine-3,5-diyl)bis([1,1′-biphenyl]-3,5-dicarboxylic acid)), MFM-170. MFM-170 exhibits fully reversible SO2 uptake of 17.5 mmol g−1 at 298 K and 1.0 bar, and the SO2 binding domains for trapped molecules within MFM-170 have been determined. We report the reversible coordination of SO2 to open Cu(ii) sites, which contributes to excellent adsorption thermodynamics and selectivities for SO2 binding and facile regeneration of MFM-170 after desorption. MFM-170 is stable to water, acid and base and shows great promise for the dynamic separation of SO2 from simulated flue gas mixtures, as confirmed by breakthrough experiments.
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Oct 2019
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B22-Multimode InfraRed imaging And Microspectroscopy
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Jack
Humby
,
Oguarabau
Benson
,
Gemma L.
Smith
,
Stephen P.
Argent
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Svemir
Rudic
,
Pascal
Manuel
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Lucy K.
Saunders
,
Inigo
Vitorica-yrezabal
,
George F. S.
Whitehead
,
Timothy L.
Easun
,
William
Lewis
,
Alexander J.
Blake
,
Anibal J.
Ramirez-cuesta
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[13666]
Open Access
Abstract: In order to develop new porous materials for applications in gas separations such as natural gas upgrading, landfill gas processing and acetylene purification it is vital to gain understanding of host-substrate interactions at a molecular level. Herein we report a series of six isoreticular metal-organic frameworks (MOFs) for selective gas adsorption. These materials do not incorporate open metal sites and thus provide an excellent platform to investigate the effect of the incorporation of ligand functionality via amide and alkyne groups on substrate binding. By reducing the linker length of our previously reported MFM-136, we report much improved CO2/CH4 (50:50) and CO2/N¬2 (15:85) selectivity values of 20.2 and 65.4, respectively (1 bar and 273 K), in the new amide-decorated MOF, MFM-126. The CO2 separation performance of MFM-126 has been confirmed by dynamic breakthrough experiments. In situ inelastic neutron scattering and synchrotron FT-IR microspectroscopy were employed to elucidate dynamic interactions of adsorbed CO2 molecules within MFM-126. Upon changing the functionality to an alkyne group in MFM-127, the CO2 uptake decreases but the C2H2 uptake increases by 68%, leading to excellent C2H2/CO2 and C2H2/CH4 selectivities of 3.7 and 21.2, respectively. Neutron powder diffraction enabled the direct observation of the preferred binding domains in MFM-126 and MFM-127, and, to the best of our knowledge, we report the first example of acetylene binding to an alkyne moiety in a porous material, with over 50% of the acetylene observed within MFM-127 displaying interactions (<4 Å) with the alkyne functionality of the framework.
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Oct 2018
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I11-High Resolution Powder Diffraction
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Simona
Pili
,
Peter
Rought
,
Daniil I.
Kolokolov
,
Longfei
Lin
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Christopher
Marsh
,
Ian P.
Silverwood
,
Victoria
García-sakai
,
Ming
Li
,
Jeremy J.
Titman
,
Lyndsey
Knight
,
Luke L.
Daemen
,
Anibal J.
Ramirez-cuesta
,
Chiu C.
Tang
,
Alexander G.
Stepanov
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[13247]
Abstract: Owing to their inherent pore structure, porous metal-organic frameworks (MOFs) can undergo post-synthetic modification, such as loading extra-framework proton carriers. However, strategies for improving the proton conductivity for non-porous MOFs are largely lacking, although increasing numbers of non-porous MOFs exhibit promising proton conductivities. Often, high humidity is required for non-porous MOFs to achieve high conductivities, but to date no clear mechanisms have been experimentally identified. Here we describe the new materials MFM-550(M), [M(HL1)], (H4L1 = biphenyl-4,4'-diphosphonic acid; M = La, Ce, Nd, Sm, Gd, Ho), MFM-550(Ba), [Ba(H2L1)], and MFM-555(M), [M(HL2)], (H4L2 = benzene-1,4-diphosphonic acid; M = La, Ce, Nd, Sm, Gd, Ho), and report enhanced proton conductivities in these non-porous materials by (i) replacing the metal ion to one with a lower oxidation state, (ii) reducing the length of the organic ligand, and (iii) introducing additional acidic protons on MOF surface. Increased framework proton density in these materials can lead to an enhancement in proton conductivity of up to four orders of magnitude. Additionally, we report a comprehensive investigation using in situ 2H NMR and neutron spectroscopy, coupled with molecular dynamic modelling, to elucidate the role of humidity in assembling interconnected networks for proton hopping. This study constructs a relationship between framework proton density and the corresponding proton conductivity in non-porous MOFs, and directly explains the role of both surface protons and external water in assembling the proton conducting pathways.
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Sep 2018
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