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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I11-High Resolution Powder Diffraction
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Xinchen
Kang
,
Lili
Li
,
Hengan
Wang
,
Tian
Luo
,
Shaojun
Xu
,
Yinlin
Chen
,
Joseph H.
Carter
,
Zi
Wang
,
Alena M.
Sheveleva
,
Kai
Lyu
,
Xue
Han
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Chiu C.
Tang
,
Lifei
Liu
,
Buxing
Han
,
Emma K.
Gibson
,
C. Richard A.
Catlow
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[33115]
Open Access
Abstract: Catalytic cleavage of β-O-4 linkages is an essential but challenging step in the depolymerisation of lignin. Here, we report the templated electrosynthesis of a hydrophobic metal-organic polyhedral catalyst (Cu-MOP-e), which exhibits excellent hydrothermal stability and exceptional activity for this reaction. The oxidative cleavage of 2-phenoxyacetophenone, 1, a lignin model compound, over Cu-MOP-e at 90 oC for 1 h affords full conversion with yields of the monomer products phenol and benzoic acid of 99%. The reusability of Cu-MOP-e has been confirmed by carrying out ten cycles of reaction. The mechanism of catalyst-substrate binding has been investigated by high resolution synchrotron X-ray powder diffraction, in situ X-ray absorption spectroscopy, electron paramagnetic resonance spectroscopy and density functional theory calculations. The combination of optimal porosity and active Cu(II) sites provides confined binding of 2-phenoxyacetophenone, thus promoting the cleavage of β-O-4 linkage under relatively mild conditions.
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Dec 2024
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I11-High Resolution Powder Diffraction
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Xiangdi
Zeng
,
Zi
Wang
,
Meng
He
,
Wanpeng
Lu
,
Wenyuan
Huang
,
Bing
An
,
Jiangnan
Li
,
Mufan
Li
,
Ben F.
Spencer
,
Sarah J.
Day
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[37155]
Open Access
Abstract: Phenylacetylene is a detrimental impurity in the polymerisation of styrene, capable of poisoning catalysts even at ppm levels and significantly degrading the quality of polystyrene. The semi-hydrogenation of phenylacetylene to styrene instead of ethylbenzene is, therefore, an important industrial process. We report a novel cerium(IV)-based metal-organic framework (denoted as Ce-bptc), which is comprised of {Ce6} clusters bridged by biphenyl-3,3’,5,5’-tetracarboxylate linkers. Ce-bptc serves as an ideal support for palladium nanoparticles and the Pd@Ce-bptc catalyst demonstrates an excellent catalytic performance for semi-hydrogenation of phenylacetylene, achieving a selectivity of 93% to styrene on full conversion under ambient conditions with excellent reusability. In situ synchrotron X-ray powder diffraction and electron paramagnetic resonance spectroscopy revealed the binding domain of phenylacetylene within Ce-bptc and details of the reaction mechanism.
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Oct 2024
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B22-Multimode InfraRed imaging And Microspectroscopy
I15-1-X-ray Pair Distribution Function (XPDF)
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Wanpeng
Lu
,
Yinlin
Chen
,
Zi
Wang
,
Jin
Chen
,
Yujie
Ma
,
Weiyao
Li
,
Jiangnan
Li
,
Meng
He
,
Mengtian
Fan
,
Alena M.
Sheveleva
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Mark D.
Frogley
,
Philip A.
Chater
,
Catherine
Dejoie
,
Martin
Schroder
,
Sihai
Yang
,
Lixia
Guo
Open Access
Abstract: The development of materials for ammonia (NH3) storage is an important and challenging task. Here, we report the high NH3 uptake in a series of copper-carboxylate materials, namely MFM-100, MFM-101, MFM-102, MFM-126, MFM-127, MFM-190(F), MFM-170, and Cu-MOP-1a. At 273 K and 1 bar, MFM-101 shows an exceptional uptake of 21.9 mmol g−1. X-ray pair distribution function analysis reveals an unusual crystalline-amorphous-crystalline phase transition for the isoreticular MFM-100, MFM-101 and MFM-102 upon adsorption and desorption of NH3 followed by regeneration in water. In situ X-ray diffraction, synchrotron infrared micro-spectroscopy, and electron paramagnetic resonance spectroscopy are employed to elucidate the presence of strong Cu(II)⋯NH3 interactions and changes in coordination at the [Cu2(O2CR)4] (R = di-, tri-, and tetra-phenyl ligands) paddlewheel.
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Sep 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[31541]
Open Access
Abstract: We report three new polymers, based on mechanically interlocked inorganic-organic rotaxanes. They are made in very mild conditions and involve pyrimidine head groups binding to copper(II) linking units. A two-dimensional 6,3 net and a three-dimensional 10,3b net are found depending on the solvent used in the reaction.
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Aug 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[31541]
Abstract: Mono- and bis-salen functionalised [2]rotaxanes have been synthesised from the esterification of [2]rotaxanes containing phenol-terminated threads (salen = N,N′-bis(salicylidene)ethylenediamine). The [2]rotaxanes have general formula [RH][Cr7NiF8(O2CtBu)16], where [RH]+ is a thread with a central secondary ammonium site that templates a [Cr7NiF8(O2CtBu)16]− ring. The threads are terminated at one or both ends by carboxylic acid functionalised salen groups. The {M(salen)} groups can be free-base [M = (H+)2] or metallated [M = Cu2+, Ni2+, (VO)2+]. The [2]rotaxanes have been characterised by single crystal XRD and solid- and solution-state EPR spectroscopy. Where two paramagnetic M ions are involved [M = Cu2+ and/or (VO)2+] the [2]rotaxanes contain three electron spin S = ½ centres, since the {Cr7Ni} ring has an S = ½ ground state which is well isolated at low temperatures. These three-spin [2]rotaxanes have been characterised in solution by pulsed dipolar EPR spectroscopies (DEER, also known as PELDOR, and RIDME). The M···M and M···{Cr7Ni} interactions measured are consistent with dipolar interactions and also with the distances from single crystal XRD.
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Jun 2024
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Lutong
Shan
,
Yujie
Ma
,
Shaojun
Xu
,
Meng
Zhou
,
Meng
He
,
Alena M.
Sheveleva
,
Rongsheng
Cai
,
Daniel
Lee
,
Yongqiang
Chen
,
Boya
Tang
,
Bing
Han
,
Yinlin
Chen
,
Lan
An
,
Tianze
Zhou
,
Martin
Wilding
,
Alexander S.
Eggeman
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Sarah J.
Day
,
Stephen P.
Thompson
,
Sarah J.
Haigh
,
Xinchen
Kang
,
Buxing
Han
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[33115, 31729]
Open Access
Abstract: The design and preparation of efficient catalysts for ammonia production under mild conditions is a desirable but highly challenging target. Here, we report a series of single-atom catalysts [M-SACs, M = Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Mo(II)] derived from UiO-66 containing structural defects and their application to electrochemical reduction of nitrate (NO3-) to ammonia (NH3). Cu-SAC and Fe-SAC exhibit remarkable yield rates for NH3 production of 30.0 and 29.0 mg h−1 cm−2, respectively, with a high Faradaic efficiency (FENH3) of over 96% at −1.0 V versus the reversible hydrogen electrode. Importantly, their catalytic performance can be retained in various simulated wastewaters. Complementary experiments confirmed the nature of single-atom sites within these catalysts and the binding domains of NO3- in UiO-66-Cu. In situ spectroscopic techniques, coupled with density functional theory calculations confirm the strong binding of NO3- and the formation of reaction intermediates, thus facilitating the catalytic conversion to NH3.
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Jun 2024
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I19-Small Molecule Single Crystal Diffraction
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Zi
Wang
,
Alena M.
Sheveleva
,
Jiangnan
Li
,
Zhengyang
Zhou
,
Sergei
Sapchenko
,
George
Whitehead
,
Mark R.
Warren
,
David
Collison
,
Junliang
Sun
,
Martin
Schroeder
,
Eric J. L.
Mcinnes
,
Sihai
Yang
,
Floriana
Tuna
Diamond Proposal Number(s):
[31627]
Open Access
Abstract: MFM-520(Zn) confines dimers of NO2 with a high adsorption of 4.52 mmol g−1 at 1 bar at 298 K. The synthesis and the incommensurate structure of Cu-doped MFM-520(Zn) are reported. The introduction of paramagnetic Cu2+ sites allows investigation of the electronic and geometric structure of metal site by in situ electron paramagnetic resonance (EPR) spectroscopy upon adsorption of NO2. By combining continuous wave and electron-nuclear double resonance spectroscopy, an unusual reverse Berry distorted coordination geometry of the Cu2+ centers is observed. Interestingly, Cu-doped MFM-520(Zn0.95Cu0.05) shows enhanced adsorption of NO2 of 5.02 mmol g−1 at 1 bar at 298 K. Whereas MFM-520(Zn) confines adsorbed NO2 as N2O4, the presence of monomeric NO2 at low temperature suggests that doping with Cu2+ centers into the framework plays an important role in tuning the dimerization of NO2 molecules in the pore via the formation of specific host-guest interactions.
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Nov 2023
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I11-High Resolution Powder Diffraction
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Tian
Luo
,
Zi
Wang
,
Yinlin
Chen
,
Hengzhao
Li
,
Mengqi
Peng
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Sarah J.
Day
,
Jie
An
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[31365]
Open Access
Abstract: Deuterium labelling of organic compounds is an important process in chemistry. We report the first example of photocatalytic dehalogenative deuteration of both arylhalides and alkylhalides (40 substrates) over a metal-organic framework, MFM-300(Cr), using CD3CN as the deuterium source at room temperature. MFM-300(Cr) catalyses high deuterium incorporation and shows excellent tolerance to various functional groups. Synchrotron X-ray powder diffraction reveals the activation of halogenated substrates via confined binding within MFM-300(Cr). In situ electron paramagnetic resonance spectroscopy confirms the formation of carbon-based radicals as intermediates and reveals the reaction pathway. This protocol removes the use of precious-metal catalysts from state-of-the-art processes based upon direct hydrogen isotope exchange and shows high photocatalytic stability, thus enabling multiple catalytic cycles.
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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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