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Abstract: Inelastic neutron scattering (INS) studies of the dynamical response of
H2
films adsorbed on MgO (1 0 0) surface are compared to and correlated with structural information from neutron diffraction measurements of equivalent
D2
films. At low coverage, a prominent peak, believed to be the para–ortho transition (usually observed at 14.7 meV in bulk
H2
) is observed at
∼11.2meV
. For film thicknesses between 0.8 and
∼3
layers this peak becomes asymmetric with additional scattering on the high-energy transfer side of the peak. As molecules are added to the third layer we observe the concomitant growth of a peak at 14.7 meV.
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Nov 2006
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NONE-No attached Diamond beamline
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Abstract: Inelastic neutron scattering is used to probe the dynamical response of H(2) films adsorbed on MgO(100) as a function of film thickness. Concomitant diffraction measurements and a reduced-dimensionality quantum dynamical model provide insight into the molecule-surface interaction potential. At monolayer thickness, the rotational motion is strongly influenced by the surface, so that the molecules behave like quasiplanar rotors. These findings have a direct impact on understanding how molecular hydrogen binds to the surface of materials used in catalytic and storage applications.
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Oct 2008
|
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I11-High Resolution Powder Diffraction
|
Sihai
Yang
,
Junliang
Sun
,
Anibal J.
Ramirez-cuesta
,
Sam
Callear
,
William I. F.
David
,
Daniel P.
Anderson
,
Ruth
Newby
,
Alexander J.
Blake
,
Julia
Parker
,
Chiu
Tang
,
Martin
Schröder
Abstract: Understanding the mechanism by which porous solids trap harmful gases such as CO2 and SO2 is essential for the design of new materials for their selective removal. Materials functionalized with amine groups dominate this field, largely because of their potential to form carbamates through H2N(delta(-))center dot center dot center dot C(delta(+))O-2 interactions, thereby trapping CO2 covalently. However, the use of these materials is energy-intensive, with significant environmental impact. Here, we report a non-amine-containing porous solid (NOTT-300) in which hydroxyl groups within pores bind CO2 and SO2 selectively. In situ powder X-ray diffraction and inelastic neutron scattering studies, combined with modelling, reveal that hydroxyl groups bind CO2 and SO2 through the formation of O=C(S)=O(delta(-))center dot center dot center dot H(delta(+))-O hydrogen bonds, which are reinforced by weak supramolecular interactions with C-H atoms on the aromatic rings of the framework. This offers the potential for the application of new 'easy-on/easy-off' capture systems for CO2 and SO2 that carry fewer economic and environmental penalties.
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Sep 2012
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|
I11-High Resolution Powder Diffraction
|
Abstract: Supramolecular interactions are fundamental to hostguest binding in many chemical and biological processes. Direct visualization of such supramolecular interactions within hostguest systems is extremely challenging, but crucial to understanding their function. We report a comprehensive study that combines neutron scattering, synchrotron X-ray and neutron diffraction, and computational modelling to define the detailed binding at a molecular level of acetylene, ethylene and ethane within the porous host NOTT-300. This study reveals simultaneous and cooperative hydrogen-bonding, Pi ...... Pi; stacking interactions and intermolecular dipole interactions in the binding of acetylene and ethylene to give up to 12 individual weak supramolecular interactions aligned within the host to form an optimal geometry for the selective binding of hydrocarbons. We also report the cooperative binding of a mixture of acetylene and ethylene within the porous host, together with the corresponding breakthrough experiments and analysis of adsorption isotherms of gas mixtures.
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Dec 2014
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
I19-Small Molecule Single Crystal Diffraction
|
Mathew
Savage
,
Yongqiang
Cheng
,
Timothy L.
Easun
,
Jennifer E.
Eyley
,
Stephen P.
Argent
,
Mark
Warren
,
William
Lewis
,
Claire
Murray
,
Chiu C.
Tang
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Junliang
Sun
,
Svemir
Rudić
,
Richard T.
Murden
,
Michael J.
Benham
,
Andrew N.
Fitch
,
Alexander J.
Blake
,
Anibal J.
Ramirez-cuesta
,
Sihai
Yang
,
Martin
Schröder
Diamond Proposal Number(s):
[9444, 5839, 12516]
Open Access
Abstract: Selective adsorption of SO2 is realized in a porous metal–organic framework material, and in-depth structural and spectroscopic investigations using X-rays, infrared, and neutrons define the underlying interactions that cause SO2 to bind more strongly than CO2 and N2.
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Aug 2016
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
|
Zhenzhong
Lu
,
Harry G. W.
Godfrey
,
Ivan
Da Silva
,
Yongqiang
Cheng
,
Mathew
Savage
,
Floriana
Tuna
,
Eric J. L.
Mcinnes
,
Simon J.
Teat
,
Kevin J.
Gagnon
,
Mark D.
Frogley
,
Pascal
Manuel
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Timothy L.
Easun
,
Sihai
Yang
,
Martin
Schröder
Diamond Proposal Number(s):
[13666]
Open Access
Abstract: Hydrogen bonds dominate many chemical and biological processes, and chemical modification enables control and modulation of host–guest systems. Here we report a targeted modification of hydrogen bonding and its effect on guest binding in redox-active materials. MFM-300(VIII) {[VIII2(OH)2(L)], LH4=biphenyl-3,3′,5,5′-tetracarboxylic acid} can be oxidized to isostructural MFM-300(VIV), [VIV2O2(L)], in which deprotonation of the bridging hydroxyl groups occurs. MFM-300(VIII) shows the second highest CO2 uptake capacity in metal-organic framework materials at 298 K and 1 bar (6.0 mmol g−1) and involves hydrogen bonding between the OH group of the host and the O-donor of CO2, which binds in an end-on manner, =1.863(1) Å. In contrast, CO2-loaded MFM-300(VIV) shows CO2 bound side-on to the oxy group and sandwiched between two phenyl groups involving a unique ···c.g.phenyl interaction [3.069(2), 3.146(3) Å]. The macroscopic packing of CO2 in the pores is directly influenced by these primary binding sites.
|
Jan 2017
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
|
Xinran
Zhang
,
Ivan
Da Silva
,
Harry G. W.
Godfrey
,
Samantha K.
Callear
,
Sergey A.
Sapchenko
,
Yongqiang
Cheng
,
Inigo J.
Vitorica-yrezabal
,
Mark D.
Frogley
,
Gianfelice
Cinque
,
Chiu C.
Tang
,
Carlotta
Giacobbe
,
Catherine
Dejoie
,
Svemir
Rudic
,
Anibal J.
Ramirez-cuesta
,
Melissa A.
Denecke
,
Sihai
Yang
,
Martin
Schroeder
Diamond Proposal Number(s):
[14341, 14938]
Abstract: During the nuclear waste disposal process, radioactive iodine in fission product can be released. The widespread implementation of sustainable nuclear energy thus requires the development of efficient iodine stores that have simultaneously high capacity, stability and more importantly, storage density (and hence minimised system volume). Here, we report high I2 adsorption in a series of robust porous metal-organic materials, MFM-300(M) (M = Al, Sc, Fe, In). MFM-300(Sc) exhibits fully reversible I2 uptake of 1.54 g g-1 and its structure remains completely unperturbed upon inclusion/removal of I2. Direct observation and quantification of the adsorption, binding domains and dynamics of guest I2 molecules within these hosts have been achieved using XPS, TGA-MS, high resolution synchrotron X-ray diffraction, pair distribution function analysis, Raman, terahertz and neutron spectroscopy, coupled with density functional theory modelling. These complimentary techniques reveal a comprehensive understanding on the host-I2 and I2-I2 binding interaction at a molecular level. The initial binding site of I2 in MFM-300(Sc), I2I, is located near the bridging hydroxyl group of the [ScO4(OH)2] moiety [I2I···H–O = 2.263(9) Å] with an occupancy of 0.268. I2II is located interstitially between two phenyl rings of neighbouring ligand molecules [I2II···phenyl ring = 3.378(9) and 4.228(5) Å]. I2II is 4.565(2) Å from the hydroxyl group with an occupancy of 0.208. Significantly, at high I2 loading an unprecedented self-aggregation of I2 molecules into triple-helical chains within the confined nano-voids has been observed at crystallographic resolution, leading to a highly efficient packing of I2 molecules with an exceptional I2 storage density of 3.08 g cm-3 in MFM-300(Sc).
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Oct 2017
|
|
I11-High Resolution Powder Diffraction
|
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.
|
Sep 2018
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
|
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.
|
Oct 2018
|
|
B22-Multimode InfraRed imaging And Microspectroscopy
|
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.
|
Oct 2019
|
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