B18-Core EXAFS
B22-Multimode InfraRed imaging And Microspectroscopy
|
Yujie
Ma
,
Wanpeng
Lu
,
Xue
Han
,
Yinlin
Chen
,
Ivan
Da Silva
,
Daniel
Lee
,
Alena M.
Sheveleva
,
Zi
Wang
,
Jiangnan
Li
,
Weiyao
Li
,
Mengtian
Fan
,
Shaojun
Xu
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Yongqiang
Cheng
,
Svemir
Rudic
,
Pascal
Manuel
,
Mark D.
Frogley
,
Anibal J.
Ramirez-Cuesta
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[19850]
Open Access
Abstract: The presence of active sites in metal–organic framework (MOF) materials can control and affect their performance significantly in adsorption and catalysis. However, revealing the interactions between the substrate and active sites in MOFs at atomic precision remains a challenging task. Here, we report the direct observation of binding of NH3 in a series of UiO-66 materials containing atomically dispersed defects and open Cu(I) and Cu(II) sites. While all MOFs in this series exhibit similar surface areas (1111–1135 m2 g–1), decoration of the −OH site in UiO-66-defect with Cu(II) results in a 43% enhancement of the isothermal uptake of NH3 at 273 K and 1.0 bar from 11.8 in UiO-66-defect to 16.9 mmol g–1 in UiO-66-CuII. A 100% enhancement of dynamic adsorption of NH3 at a concentration level of 630 ppm from 2.07 mmol g–1 in UiO-66-defect to 4.15 mmol g–1 in UiO-66-CuII at 298 K is observed. In situ neutron powder diffraction, inelastic neutron scattering, and electron paramagnetic resonance, solid-state nuclear magnetic resonance, and infrared spectroscopies, coupled with modeling reveal that the enhanced NH3 uptake in UiO-66-CuII originates from a {Cu(II)···NH3} interaction, with a reversible change in geometry at Cu(II) from near-linear to trigonal coordination. This work represents the first example of structural elucidation of NH3 binding in MOFs containing open metal sites and will inform the design of new efficient MOF sorbents by targeted control of active sites for NH3 capture and storage.
|
May 2022
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
|
Lixia
Guo
,
Xue
Han
,
Yujie
Ma
,
Jiangnan
Li
,
Wanpeng
Lu
,
Weiyao
Li
,
Daniel
Lee
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Svemir
Rudic
,
Pascal
Manuel
,
Mark D.
Frogley
,
Anibal Javier
Ramirez-Cuesta
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[30398]
Open Access
Abstract: To understand the exceptional adsorption of ammonia (NH3) in MFM-300(Sc) (19.5 mmol g−1 at 273 K and 1 bar without hysteresis), we report a systematic investigation of the mechanism of adsorption by a combination of in situ neutron powder diffraction, inelastic neutron scattering, synchrotron infrared microspectroscopy, and solid-state 45Sc NMR spectroscopy. These complementary techniques reveal the formation of reversible host-guest supramolecular interactions, which explains directly the observed excellent reversibility of this material over 90 adsorption-desorption cycles.
|
Apr 2022
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
|
Sihai
Yang
,
Zongsu
Han
,
Jiangnan
Li
,
Wanpeng
Lu
,
Kunyun
Wang
,
Yinlin
Chen
,
Xiaoping
Zhang
,
Longfei
Lin
,
Xue
Han
,
Simon
Teat
,
Mark
Frogley
,
Wei
Shi
,
Peng
Cheng
Diamond Proposal Number(s):
[23782]
Abstract: Air pollutions by SO2 and NO2 have caused significant risks on the environment and human health. Understanding the mechanism of active sites within capture materials is of fundamental importance to the development of new clean-up technologies. Here we report the crystallographic observation of reversible coordinative binding of SO2 and NO2 on open Ni(II) sites in a metal-organic framework (NKU-100) incorporating an unprecedented {Ni 12 }-wheel, which exhibits six open Ni(II) sites on desolvation. Immobilised gas molecules are further stabilised by cooperative host-guest interactions comprised of hydrogen bonds, π ··· π interactions and dipole interactions. At 298 K and 1.0 bar, NKU-100 shows adsorption uptakes of 6.21 and 5.80 mmol g -1 for SO2 and NO2 , respectively. Dynamic breakthrough experiments have confirmed the selective retention of SO2 and NO2 at low concentrations under dry conditions. This work will inspire the future design of efficient sorbents for the capture of SO2 and NO2 .
|
Nov 2021
|
|
I11-High Resolution Powder Diffraction
|
Tian
Luo
,
Lili
Li
,
Yinlin
Chen
,
Jie
An
,
Chengcheng
Liu
,
Zheng
Yan
,
Joseph H.
Carter
,
Xue
Han
,
Alena M.
Sheveleva
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Chiu C.
Tang
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[15972]
Open Access
Abstract: Construction of C-C bonds via reductive coupling of aldehydes and ketones is hindered by the highly negative reduction potential of these carbonyl substrates, particularly ketones, and this renders the formation of ketyl radicals extremely endergonic. Here, we report the efficient activation of carbonyl compounds by the formation of specific host-guest interactions in a hydroxyl-decorated porous photocatalyst. MFM-300(Cr) exhibits a band gap of 1.75 eV and shows excellent catalytic activity and stability towards the photoreductive coupling of 30 different aldehydes and ketones to the corresponding 1,2-diols at room temperature. Synchrotron X-ray diffraction and electron paramagnetic resonance spectroscopy confirm the generation of ketyl radicals via confinement within MFM-300(Cr). This protocol removes simultaneously the need for a precious metal-based photocatalyst or for amine-based sacrificial agents for the photochemical synthesis.
|
Jun 2021
|
|
I11-High Resolution Powder Diffraction
|
Martin
Schroeder
,
Louis
Kimberley
,
Alena M.
Sheveleva
,
Jiangnan
Li
,
Joseph H.
Carter
,
Xinchen
Kang
,
Gemma L.
Smith
,
Xue
Han
,
Sarah J.
Day
,
Chiu C.
Tang
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Sihai
Yang
Open Access
Abstract: Selective oxidation of benzylic C‐H compounds to ketones is important for the production of a wide range of fine chemicals, and is often achieved using toxic or precious metals catalysts. Here, we report the efficient oxidation of benzylic C‐H groups in a broad range of substrates under mild conditions over a robust metal‐organic framework material, MFM‐170, incorporating redox‐active [Cu2II(O2CR)4] paddlewheel nodes. A comprehensive investigation employing electron paramagnetic resonance (EPR) spectroscopy and synchrotron X‐ray diffraction has identified the critical role of the paddlewheel moiety in activating the oxidant tBuOOH (t‐butyl hydroperoxide) via partial reduction to [CuIICuI(O2CR)4] species.
|
Apr 2021
|
|
I11-High Resolution Powder Diffraction
I19-Small Molecule Single Crystal Diffraction
|
Christopher
Marsh
,
Xue
Han
,
Jiangnan
Li
,
Zhenzhong
Lu
,
Stephen
Argent
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Anibal J.
Ramirez-Cuesta
,
Stephen P.
Thompson
,
Alexander J.
Blake
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[23483, 11622]
Open Access
Abstract: We report the reversible adsorption of ammonia (NH3) up to 9.9 mmol g–1 in a robust Al-based metal–organic framework, MFM-303(Al), which is functionalized with free carboxylic acid and hydroxyl groups. The unique pore environment decorated with these acidic sites results in an exceptional packing density of NH3 at 293 K (0.801 g cm–3) comparable to that of solid NH3 at 193 K (0.817 g cm–3). In situ synchrotron X-ray diffraction and inelastic neutron scattering reveal the critical role of free −COOH and −OH groups in immobilizing NH3 molecules. Breakthrough experiments confirm the excellent performance of MFM-303(Al) for the capture of NH3 at low concentrations under both dry and wet conditions.
|
Apr 2021
|
|
B18-Core EXAFS
B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
|
Shaojun
Xu
,
Xue
Han
,
Yujie
Ma
,
Thien D.
Duong
,
Longfei
Lin
,
Emma K.
Gibson
,
Alena
Sheveleva
,
Sarayute
Chansai
,
Alex
Walton
,
Duc-The
Ngo
,
Mark D.
Frogley
,
Chiu C.
Tang
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
C. Richard A.
Catlow
,
Christopher
Hardacre
,
Sihai
Yang
,
Martin
Schroeder
Open Access
Abstract: Efficient catalytic conversion of NO2 to non-harmful species remains an important target for research. State-of-the-art deNOx processes are based upon ammonia (NH3)-assisted selective catalytic reduction (NH3-SCR) over Cu-exchanged zeolites at elevated temperatures. Here, we describe a highly efficient non-thermal plasma (NTP) deNOx process catalyzed by a Cu-embedded metal-organic framework, Cu/MFM-300(Al), at room temperature. Under NTP activation at 25°C, Cu/MFM-300(Al) enables direct decomposition of NO2 into N2, NO, N2O, and O2 without the use of NH3 or other reducing agents. NO2 conversion of 96% with a N2 selectivity of 82% at a turnover frequency of 2.9 h−1 is achieved, comparable to leading NH3-SCR catalysts that use NH3 operating at 250°C–550°C. The mechanism for the rate-determining step (NO→N2) is elucidated by in operando diffuse reflectance infrared Fourier transform spectroscopy, and electron paramagnetic resonance spectroscopy confirms the formation of Cu2+⋯NO nitrosylic adducts on Cu/MFM-300(Al), which facilitates NO dissociation and results in the notable N2 selectivity.
|
Feb 2021
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
|
Xue
Han
,
Wanpeng
Lu
,
Yinlin
Chen
,
Ivan
Da Silva
,
Jiangnan
Li
,
Longfei
Lin
,
Weiyao
Li
,
Alena M.
Sheveleva
,
Harry G. W.
Godfrey
,
Zhenzhong
Lu
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Yongqiang
Cheng
,
Luke L.
Daemen
,
Laura J.
Mccormick Mcpherson
,
Simon J.
Teat
,
Mark D.
Frogley
,
Svemir
Rudic
,
Pascal
Manuel
,
Anibal J.
Ramirez-Cuesta
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[23782]
Abstract: Ammonia (NH3) is a promising energy resource owing to its high hydrogen density. However, its widespread application is restricted by the lack of efficient and corrosion-resistant storage materials. Here, we report high NH3 adsorption in a series of robust metal–organic framework (MOF) materials, MFM-300(M) (M = Fe, V, Cr, In). MFM-300(M) (M = Fe, VIII, Cr) show fully reversible capacity for >20 cycles, reaching capacities of 16.1, 15.6, and 14.0 mmol g–1, respectively, at 273 K and 1 bar. Under the same conditions, MFM-300(VIV) exhibits the highest uptake among this series of MOFs of 17.3 mmol g–1. In situ neutron powder diffraction, single-crystal X-ray diffraction, and electron paramagnetic resonance spectroscopy confirm that the redox-active V center enables host–guest charge transfer, with VIV being reduced to VIII and NH3 being oxidized to hydrazine (N2H4). A combination of in situ inelastic neutron scattering and DFT modeling has revealed the binding dynamics of adsorbed NH3 within these MOFs to afford a comprehensive insight into the application of MOF materials to the adsorption and conversion of NH3.
|
Feb 2021
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
|
Lydia
Briggs
,
Ruth
Newby
,
Xue
Han
,
Christopher
Morris
,
Mathew
Savage
,
Cristina
Perez
,
Timothy L.
Easun
,
Mark
Frogley
,
Gianfelice
Cinque
,
Claire A.
Murray
,
Chiu C.
Tang
,
Sihai
Yang
,
Junliang
Sun
,
Martin
Schroeder
Diamond Proposal Number(s):
[22137, 22138]
Open Access
Abstract: We report the adsorption of C2H2, CO2 and SO2 in a new, ultra-stable Cr(III)-based MOF, MFM-300(Cr), {[Cr2(OH)2(L)], H4L = biphenyl-3,3',5,5'-tetracarboxylic acid}. MFM-300(Cr) shows uptakes of 7.37, 7.73 and 8.59 mmol g-1 for CO2, C2H2 and SO2, respectively, at 273 K, 1.0 bar, and shows a higher selectivity for SO2/CO2 compared with the Al(III) analogue MFM-300(Al) (selectivity of 79 vs. 45). In order to monitor the effects of changing metal centre on gas uptake and to integrate the properties of the homometallic analogues, the mixed metal MFM-300(Al0.67Cr0.33), [Al1.34Cr0.66(OH)2L] has been synthesised. In situ synchrotron micro-FTIR spectroscopy has identified distinct CO2 binding environments on Al-O(H)-Al, Cr-O(H)-Cr and Al-O(H)-Cr bridges in MFM-300(Al0.67Cr0.33), and we have determined the binding domains for these gases by in situ synchrotron X-ray diffraction in both MFM-300(Cr) and MFM-300(Al0.67Cr0.33). The capability of these materials for gas separation has been confirmed by dynamic breakthrough experiments. The incorporation of Al(III) and Cr(III) within the same framework allows tuning of the host-guest and guest-guest interactions within these functional porous materials.
|
Feb 2021
|
|
I11-High Resolution Powder Diffraction
I20-EDE-Energy Dispersive EXAFS (EDE)
|
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.
|
Feb 2021
|
|
