I15-1-X-ray Pair Distribution Function (XPDF)
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Celia
Castillo-Blas
,
Montaña J.
García
,
Ashleigh M.
Chester
,
Matjaž
Mazaj
,
Shaoliang
Guan
,
Georgina P.
Robertson
,
Ayano
Kono
,
James M. A.
Steele
,
Luis
León-Alcaide
,
Bruno
Poletto-Rodrigues
,
Philip A.
Chater
,
Silvia
Cabrera
,
Andraž
Krajnc
,
Lothar
Wondraczek
,
David A.
Keen
,
Jose
Alemán
,
Thomas
Bennett
Diamond Proposal Number(s):
[29957]
Open Access
Abstract: Metal–organic framework (MOF) composites are proposed as solutions to the mechanical instability of pure MOF materials. Here, we present a new compositional series of recently discovered MOF–crystalline inorganic glass composites. In this case, formed by the combination of a photocatalytic titanium MOF (MIL-125-NH2) and a phosphate-based glass (20%Na2O–10%Na2SO4–70%P2O5). This new family of composites has been synthesized and characterized using powder X-ray diffraction, thermal gravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and X-ray total scattering. Through analysis of the pair distribution function extracted from X-ray total scattering data, the atom–atom interactions at the MOF–glass interface are described. Nitrogen and carbon dioxide isotherms demonstrate good surface area values despite the pelletization and mixing of the MOF with a dense inorganic glass. The catalytic activity of these materials was investigated in the photooxidation of amines to imines, showing the retention of the photocatalytic effectiveness of the parent pristine MOF.
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Mar 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Shichun
Li
,
Chao
Ma
,
Jingwei
Hou
,
Shuwen
Yu
,
Aibing
Chen
,
Juan
Du
,
Philip A.
Chater
,
Dean S.
Keeble
,
Zhihua
Qiao
,
Chongli
Zhong
,
David A.
Keen
,
Yu
Liu
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038]
Open Access
Abstract: Crystalline metal-organic frameworks (MOFs) exhibit enormous potential application in gas separation, thanks to their highly porous structures and precise pore size distributions. Nevertheless, the inherent limitations in mechanical stability of crystalline MOFs cause challenges in processing MOF powders into bulky structures, particularly for membrane filtrations. Melt-quenched MOF glasses boast excellent processability due to liquid-like properties. However, the melting process diminishes the inherent porosity, leading to reduced gas adsorption capacities and lower gas diffusion coefficients. In this work, we demonstrated that enhancing the porosity of MOF glasses is achievable through topological engineering on the crystalline precursors. Crystalline zeolitic imidazolate frameworks (ZIFs) with large 12-membered rings pores, including AFI and CAN topology, were synthesized by using both structure-directing agents and mixed organic ligands. The large pores are partially preserved in the melt-quenched glass as evidenced by high-pressure CO2 absorption at 3000 kPa. The agAFI-[Zn(Im)1.68(bIm)0.32] glass was then fabricated into self-supported membranes, which shows high gas separation performance, for example, CO2 permeance of 3.7 × 104 GPU with a CO2/N2 selectivity of 14.8.
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Feb 2025
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I15-1-X-ray Pair Distribution Function (XPDF)
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Bikash Kumar
Shaw
,
Lucia
Corti
,
Joshua M.
Tuffnell
,
Celia
Castillo-Blas
,
Patrick
Schlachta
,
Georgina P.
Robertson
,
Lauren
Mchugh
,
Adam F.
Sapnik
,
Sebastian A.
Hallweger
,
Philip A.
Chater
,
Gregor
Kieslich
,
David A.
Keen
,
Sian E.
Dutton
,
Frédéric
Blanc
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038]
Open Access
Abstract: ABX3-type hybrid organic–inorganic structures have recently emerged as a new class of meltable materials. Here, by the use of phenylphosphonium derivatives as A cation, we study liquid- and glass-forming behavior of a new family of hybrid structures, (RPh3P)[Mn(dca)3] (R = Me, Et, Ph; dca = dicyanamide). These new compounds melt at 196–237 °C (Tm) and then vitrify upon cooling to room temperature, forming glasses. In situ glass formation of this new family of materials was probed on a large scale using a variable-temperature PXRD experiment. Structure analyses of the crystalline and the glasses were carried out by solid-state nuclear magnetic resonance spectroscopy and synchrotron X-ray total scattering techniques for using the pair distribution function. The mechanical properties of the glasses produced were evaluated showing promising durability. Thermal and electrical conductivities showed low thermal conductivities (κ ∼ 0.07–0.09 W m–1 K–1) and moderate electrical conductivities (σ ∼ 10–4–10–6 S m–1) at room temperature, suggesting that by the precise control of the A cation, we can tune meltable hybrid structures from moderate conductors to efficient thermal insulators. Our results raise attention on the practical use of this new hybrid material in applications including, e.g., photovoltaic devices to prevent light-deposited heat (owing to low κRT), energy harvesting thermoelectric, etc., and advance the structure–property understanding.
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Dec 2024
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I09-Surface and Interface Structural Analysis
I15-1-X-ray Pair Distribution Function (XPDF)
I21-Resonant Inelastic X-ray Scattering (RIXS)
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Liquan
Pi
,
Erik
Bjorklund
,
Gregory J.
Rees
,
Weixin
Song
,
Chen
Gong
,
John-Joseph
Marie
,
Xiangwen
Gao
,
Shengda D.
Pu
,
Mikkel
Juelsholt
,
Philip A.
Chater
,
Joohyuk
Park
,
Min Gyu
Kim
,
Jaewon
Choi
,
Stefano
Agrestini
,
Mirian
Garcia-Fernandez
,
Ke-Jin
Zhou
,
Alex W.
Robertson
,
Robert S.
Weatherup
,
Robert A.
House
,
Peter G.
Bruce
Diamond Proposal Number(s):
[27336, 29028, 25807]
Abstract: Disordered rocksalt cathodes deliver high energy densities, but they suffer from pronounced capacity and voltage fade on cycling. Here, we investigate fade using two disordered rocksalt lithium manganese oxyfluorides: Li3Mn2O3F2 (Li1.2Mn0.8O1.2F0.8), which stores charge by Mn2+/Mn4+ redox, and Li2MnO2F, where charge storage involves both Mn3+/Mn4+ and oxygen redox (O-redox). Li3Mn2O3F2 is reported for the first time. We identify the growth of an electronically resistive surface layer with cycling that is present in both Li2MnO2F and Li3Mn2O3F2 but more pronounced in the presence of O-redox. This resistive surface inhibits electronic contact between particles, leading to the observed voltage polarization and capacity loss. By increasing carbon loading in the composite cathode, it is possible to substantially improve the cycling performance. These results help to disentangle O-redox from other leading causes of capacity fading in Mn oxyfluorides and highlight the importance of maintaining electronic conductivity in improving capacity and voltage retention.
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Dec 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
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Marcin W.
Orzech
,
Francesco
Mazzali
,
Arturas
Adomkevicius
,
Mauro
Coduri
,
Yubiao
Niu
,
James D.
Mcgettrick
,
Philip A.
Chater
,
Laura
Cabo-Fernandez
,
Laurence J.
Hardwick
,
Lorenzo
Malavasi
,
Serena
Margadonna
Diamond Proposal Number(s):
[19325]
Open Access
Abstract: Sodium-ion batteries represent a sustainable and cost-effective solution for grid-scale energy storage. However, the reliance on cathode materials containing scarce transition metals currently limits their wider adoption. Carbonaceous materials present an environmentally sustainable and economically viable alternative. This study investigates application of reduced graphene oxide as a cathode active material. Detailed analysis of the storage mechanism and its dependency on the morphological and chemical structure, revealed that the key factors responsible for high capacity and long cycle life are the open structure of graphene sheets and the presence of functional oxygen and nitrogen groups. Good understanding of the mechanism allowed optimisation of cycling conditions in a proof-of-concept all-carbon full cell incorporating reduced graphene oxide and hard carbon as cathode and anode, respectively. The system displays good energy density (80 Wh kg-1) and remarkable stability over 500 cycles. The gained insights will support rational design of more efficient carbonaceous electrodes.
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Sep 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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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[34807]
Open Access
Abstract: Li-excess Mn-based disordered rock salt oxides (DRX) are promising Li-ion cathode materials owing to their cost-effectiveness and high theoretical capacities. It has recently been shown that Mn-rich DRX Li1+xMnyM1–x–yO2 (y ≥ 0.5, M are hypervalent ions such as Ti4+ and Nb5+) exhibit a gradual capacity increase during the first few charge–discharge cycles, which coincides with the emergence of spinel-like domains within the long-range DRX structure coined as “δ phase”. Here, we systematically study the structural evolution upon heating of Mn-based DRX at different levels of delithiation to gain insight into the structural rearrangements occurring during battery cycling and the mechanism behind δ phase formation. We find in all cases that the original DRX structure relaxes to a δ phase, which in turn leads to capacity enhancement. Synchrotron X-ray and neutron diffraction were employed to examine the structure of the δ phase, revealing that selective migration of Li and Mn/Ti cations to different crystallographic sites within the DRX structure leads to the observed structural rearrangements. Additionally, we show that both Mn-rich (y ≥ 0.5) and Mn-poor (y < 0.5) DRX can thermally relax into a δ phase after delithiation, but the relaxation processes in these distinct compositions lead to different domain structures. Thermochemical studies and in situ heating XRD experiments further indicate that the structural relaxation has a larger thermodynamic driving force and a lower activation energy for Mn-rich DRX, as compared to Mn-poor systems, which underpins why this structural evolution is only observed for Mn-rich systems during battery cycling.
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Aug 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
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Vahid
Nozari
,
Ayda Nemati Vesali
Azar
,
Roman
Sajzew
,
Celia
Castillo-Blas
,
Ayano
Kono
,
Martin
Oschatz
,
David A.
Keen
,
Philip A.
Chater
,
Georgina P.
Robertson
,
James M. A.
Steele
,
Luis
León-Alcaide
,
Alexander
Knebel
,
Christopher W.
Ashling
,
Thomas D.
Bennett
,
Lothar
Wondraczek
Diamond Proposal Number(s):
[29957]
Open Access
Abstract: Metal-organic framework (MOF) composite materials containing ionic liquids (ILs) have been proposed for a range of potential applications, including gas separation, ion conduction, and hybrid glass formation. Here, an order transition in an IL@MOF composite is discovered using CuBTC (copper benzene-1,3,5-tricarboxylate) and [EMIM][TFSI] (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide). This transition – absent for the bare MOF or IL – provides an extended super-cooling range and latent heat at a capacity similar to that of soft paraffins, in the temperature range of ≈220 °C. Structural analysis and in situ monitoring indicate an electrostatic interaction between the IL molecules and the Cu paddle-wheels, leading to a decrease in pore symmetry at low temperature. These interactions are reversibly released above the transition temperature, which reflects in a volume expansion of the MOF-IL composite.
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Jul 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[30086]
Open Access
Abstract: The thermal transformation of zircon to scheelite in BiVO4 was studied by in-situ Synchrotron X-ray diffraction and TGA/FTIR analysis. Upon heating, the tetragonal zircon polymorph of BiVO4 (tz-BiVO4) transitioned to the tetragonal scheelite (ts-)polymorph between 693-773 K, then to monoclinic fergusonite (mf) polymorph upon cooling. An anomaly in thermal expansion was observed between 400-500 K, associated with loss of H2O/NH4+. Heating tz-BiVO4 resulted in contraction of the V-O bond distance and VO4 polyhedra volume due to rotation of the VO4. Attempts to study this by neutron diffraction failed due to the large incoherent scatter from the hydrogenous species. Efforts to remove these species while maintaining the tz-BiVO4 structure were unsuccessful, suggesting they play a role in stabilizing the zircon polymorph. The local structure of both mf-BiVO4 and tz-BiVO4 were investigated by X-ray Pair Distribution Function analysis.
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May 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[30086]
Abstract: Scheelite-type metal oxides are a notable class of functional materials, with applications including ionic conductivity, photocatalysis, and the safe storage of radioactive waste. To further engineer these materials for specific applications, a detailed understanding of how their properties can change under different conditions is required─not just in the long-range average structure but also in the short-range local structure. This paper outlines a detailed investigation of the metal oxide CsReO4, which exhibits an uncommon orthorhombic Pnma pseudo-scheelite-type structure at room temperature. Using synchrotron X-ray diffraction, the average structure of CsReO4 is found to undergo a transformation from the orthorhombic Pnma pseudo-scheelite-type structure to the tetragonal I41/a scheelite-type structure at ∼440 K. In the X-ray pair distribution function analysis, lattice strain and rotations of the ReO4 tetrahedra are apparent above 440 K despite the increase in long-range average symmetry, revealing a disconnect between the structural models at different length scales. This study demonstrates how the bonding requirements and ionic radii of the A-site cation can induce disorder that is detectable at different length scales, affecting the physical properties of the material.
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May 2024
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