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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Emily V.
Shaw
,
Celia
Castillo Blas
,
Timothy
Lambden
,
Beatriz
De Santos
,
Bethan
Turner
,
Giulio I.
Lampronti
,
Joonatan E. M.
Laulainen
,
Georgina
Robertson
,
Ashleigh M.
Chester
,
Chumei
Ye
,
Shaoliang
Guan
,
Joshua
Karlsson
,
Valentina
Martinez
,
Ivana
Brekalo
,
Bahar
Karadeniz
,
Silvia
Cabrera
,
Lauren N.
Mchugh
,
Krunoslav
Užarević
,
Jose
Aleman
,
Alberto
Fraile
,
Rachel C
Evans
,
Paul
Midgley
,
David A.
Keen
,
Xavier
Moya
,
Thomas D.
Bennett
Open Access
Abstract: In this work, we investigated the response of the metal-organic framework MIL-125-NH2 to ball-milling. Both localised and bulk analyses revealed that prolongued ball-milling results in a complete loss of long-range structural order. Investigation of this disorder revealed partial retention of the local bonding of the secondary building unit, suggesting structure collapse progressed primarily through metal-linker bond breakage. We explored the photocatalytic performance of the materials, and examined the materials’ band gap using UV-Vis reflectance spectroscopy.
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Feb 2025
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[35729]
Open Access
Abstract: The production of H2-rich syngas from pyrolysis-catalytic gasification of plastic waste bottles has been investigated. The hybrid-functional materials consisting of Ni as catalyst, CaO as CO2 sorbent and Ca2SiO4 as a polymorphic active spacer were synthesized. The different parameters (Ni loading, temperature, N2 flow rate and feedstock-to-catalyst ratio) have been investigated to optimise the H2 production. The catalysts were analysed by N2 physisorption, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Temperature-programmed reduction (TPR) and in-situ Transmission Electron Microscopy (TEM). Temperature-programmed oxidation (TPO) was used to analyse the carbon formation on the used catalysts. The highest H2 production of 59.15 mmol g-1of plastic was obtained in the presence of a catalyst with 20 wt.% Ni loading, which amounts to H2 purity as high as 54.2 vol% in gas production. Furthermore, 90.63 mmol g-1of plastic of syngas was produced by increasing the feedstock-to-catalyst ratio to 4:1, yielding 84.4 vol.% of total gas product (53.1 vol.% of H2 and 31.3 vol.% of CO, respectively). The Ni-CaO-Ca2SiO4 hybrid-functional material is a very promising catalyst in the pyrolysis-catalytic gasification process by capturing CO2 as it is produced, therefore shifting the water gas shift (WGS) reaction to enhance H2 production from plastic waste. Detailed elucidation of the roles of each component at the microscale during the catalytic process was also provided through in-situ TEM analysis. The finding could guide the industry for future large-scale application to convert abundant plastic waste into H2-rich syngas, therefore contributing to the global ‘net zero’ ambition.
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Jan 2025
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B18-Core EXAFS
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Santhosh K.
Matam
,
Preetam K.
Sharma
,
Eileen H.
Yu
,
Charalampos
Drivas
,
Mohammad D.
Khan
,
Martin
Wilding
,
Nitya
Ramanan
,
Diego
Gianolio
,
Mark A.
Isaacs
,
Shaoliang
Guan
,
Philip R.
Davies
,
C. Richard A.
Catlow
Diamond Proposal Number(s):
[29271]
Open Access
Abstract: We present a novel operando X-ray absorption spectroscopic (XAS) flow cell, consisting of a gas chamber for CO2 and a liquid chamber for the electrolyte, to monitor electrochemical CO2 reduction (eCO2R) over a gas diffusion electrode (GDE). The feasibility of the flow cell is demonstrated by collecting XAS data (during eCO2R over Cu-GDE) in a transmission mode at the Cu K-edge. The dynamic behaviour of copper during eCO2R is captured by XAS which is complemented by quasi in situ Raman and X-ray photoelectron spectroscopy (XPS). The linear combination analyses (LCA) of X-ray absorption near edge structure (XANES) indicate that copper oxides are the only species present during the first 20 min of eCO2R, corroborated by complementary Raman and XPS. Significantly, the complementary spectroscopic data suggests that the copper composition in the bulk and on the surface Cu-GDE evolve differently at and above 30 min of eCO2R. LCA indicates that at 60 min, 77% of copper occurs as metallic Cu and the remainder 23% in Cu (II) oxidation state, which is not evident from XPS that shows 100% of copper in < 2+ oxidation state. Thus, the Cu (II) is probably in the bulk of Cu-GDE, as also evident from Raman. The ethylene formation correlates very well with the occurrence of copper oxides and hydroxide species in Cu-GDE. The results not only demonstrate the applicability and versatility of the operando XAS GDE flow cell, but also illustrate the unique advantages of combining XAS with complementary Raman and XPS that enables the monitoring of the catalyst structural evolution from the bulk to surface and surface adsorbed species.
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Dec 2024
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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
E01-JEM ARM 200CF
I09-Surface and Interface Structural Analysis
I20-EDE-Energy Dispersive EXAFS (EDE)
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Xuze
Guan
,
Rong
Han
,
Hiroyuki
Asakura
,
Bolun
Wang
,
Lu
Chen
,
Jay Hon Cheung
Yan
,
Shaoliang
Guan
,
Luke
Keenan
,
Shusaku
Hayama
,
Matthijs A.
Van Spronsen
,
Georg
Held
,
Jie
Zhang
,
Hao
Gu
,
Yifei
Ren
,
Lun
Zhang
,
Zhangyi
Yao
,
Yujiang
Zhu
,
Anna
Regoutz
,
Tsunehiro
Tanaka
,
Yuzheng
Guo
,
Feng Ryan
Wang
Diamond Proposal Number(s):
[23759, 24450, 29092, 31852]
Open Access
Abstract: Single-atom catalysts have garnered significant attention due to their exceptional atom utilization and unique properties. However, the practical application of these catalysts is often impeded by challenges such as sintering-induced instability and poisoning of isolated atoms due to strong gas adsorption. In this study, we employed the mechanochemical method to insert single Cu atoms into the subsurface of Fe2O3 support. By manipulating the location of single atoms at the surface or subsurface, catalysts with distinct adsorption properties and reaction mechanisms can be achieved. It was observed that the subsurface Cu single atoms in Fe2O3 remained isolated under both oxidation and reduction environments, whereas surface Cu single atoms on Fe2O3 experienced sintering under reduction conditions. The unique properties of these subsurface single-atom catalysts call for innovations and new understandings in catalyst design.
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Jul 2024
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E01-JEM ARM 200CF
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Shanshan
Xu
,
Thomas J. A.
Slater
,
Hong
Huang
,
Yangtao
Zhou
,
Yilai
Jiao
,
Christopher M. A.
Parlett
,
Shaoliang
Guan
,
Sarayute
Chansai
,
Shaojun
Xu
,
Xinrui
Wang
,
Christopher
Hardacre
,
Xiaolei
Fan
Diamond Proposal Number(s):
[29468]
Open Access
Abstract: The stability of catalysts in dry reforming of methane (DRM) is a known issue. In this paper an encapsulation strategy has been employed to improve the stability compared with conventional impregnation methods. Herein, nickel nanoparticles encapsulated in silicalite-1 were prepared using a range of methods including post treatment, direct hydrothermal and seed-directed methods to investigate the effect of synthesis protocol on the properties of catalysts, such as degree of encapsulation and Ni dispersion, and anti-coking/-sintering performance in DRM. The Ni@SiO2-S1 catalysts obtained by the seed-directed synthesis presented the full encapsulation of Ni NPs by the zeolite framework with small particle sizes (∼2.9 nm) and strong metal-support interaction, which could sterically hinder the migration/aggregation of Ni NPs and carbon deposition. Therefore, Ni@SiO2-S1 showed stable CO2/CH4 conversions of 80% and 73%, respectively, with negligible metal sintering and coking deposition (∼0.5 wt.%) over 28 h, which outperformed the other catalysts prepared. In contrast, the catalysts developed by the post-treatment and ethylenediamine-protected hydrothermal methods showed the co-existence of Ni phase on the internal and external surfaces, i.e. incomplete encapsulation, with large Ni particles, contributing to Ni sintering and coking. The correlation of the synthesis-structure-performance in this study sheds light on the design of coking-/sintering-resistant encapsulated catalysts for DRM.
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Jun 2022
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Liqun
Kang
,
Bolun
Wang
,
Andreas T.
Güntner
,
Siyuan
Xu
,
Xuhao
Wan
,
Yiyun
Liu
,
Sushila
Marlow
,
Yifei
Ren
,
Diego
Gianolio
,
Chiu C.
Tang
,
Vadim
Murzin
,
Hiroyuki
Asakura
,
Qian
He
,
Shaoliang
Guan
,
Juan J.
Velasco-Vélez
,
Sotiris E.
Pratsinis
,
Yuzheng
Guo
,
Feng Ryan
Wang
Open Access
Abstract: Electronic metal‐support interaction (EMSI) describes the electron flow between metal sites and a metal oxide support. It is generally used to follow the mechanism of redox reactions. In the study of CuO‐CeO2 redox, an additional flow of electron from metallic Cu to surface carbon species is observed via a combination of operando X‐ray absorption spectroscopy, synchrotron X‐ray powder diffraction, near ambient pressure‐near edge X‐ray absorption fine structure, and diffuse reflectance infrared Fourier transform spectroscopy. An electronic metal‐support‐carbon interaction (EMSCI) is proposed to explain the reaction pathway of CO oxidation. The EMSCI provides a complete picture of the mass and electron flow, which will help predict and improve the catalytic performance in the selective activation of CO2 , carbonate or carbonyl species in C1 chemistry.
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Mar 2021
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Benzhen
Yao
,
Tiancun
Xiao
,
Ofentse A.
Makgae
,
Xiangyu
Jie
,
Sergio
Gonzalez-Cortes
,
Shaoliang
Guan
,
Angus I.
Kirkland
,
Jonathan R.
Dilworth
,
Hamid A.
Al-Megren
,
Saeed M.
Alshihri
,
Peter J.
Dobson
,
Gari P.
Owen
,
John M.
Thomas
,
Peter P.
Edwards
Open Access
Abstract: With mounting concerns over climate change, the utilisation or conversion of carbon dioxide into sustainable, synthetic hydrocarbons fuels, most notably for transportation purposes, continues to attract worldwide interest. This is particularly true in the search for sustainable or renewable aviation fuels. These offer considerable potential since, instead of consuming fossil crude oil, the fuels are produced from carbon dioxide using sustainable renewable hydrogen and energy. We report here a synthetic protocol to the fixation of carbon dioxide by converting it directly into aviation jet fuel using novel, inexpensive iron-based catalysts. We prepare the Fe-Mn-K catalyst by the so-called Organic Combustion Method, and the catalyst shows a carbon dioxide conversion through hydrogenation to hydrocarbons in the aviation jet fuel range of 38.2%, with a yield of 17.2%, and a selectivity of 47.8%, and with an attendant low carbon monoxide (5.6%) and methane selectivity (10.4%). The conversion reaction also produces light olefins ethylene, propylene, and butenes, totalling a yield of 8.7%, which are important raw materials for the petrochemical industry and are presently also only obtained from fossil crude oil. As this carbon dioxide is extracted from air, and re-emitted from jet fuels when combusted in flight, the overall effect is a carbon-neutral fuel. This contrasts with jet fuels produced from hydrocarbon fossil sources where the combustion process unlocks the fossil carbon and places it into the atmosphere, in longevity, as aerial carbon - carbon dioxide.
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Dec 2020
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B18-Core EXAFS
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Diamond Proposal Number(s):
[15151]
Open Access
Abstract: The control of the growth of hematite nanoparticles from iron chloride solutions under hydrothermal conditions in the presence of two different structure promoters has been studied using a range of both structural and spectroscopic techniques including the first report of photo induced force microscopy (PiFM) to map the topographic distribution of the structure-directing agents on the developing nanoparticles. We show that the shape of the nanoparticles can be controlled using the concentration of phosphate ions up to a limit determined to be ~6 × 10−3 mol. Akaganéite (β-FeOOH) is a major component of the nanoparticles formed in the absence of structure directors but only present in the very early stages (< 8 h) of particle growth when phosphate is present. The PiFM data suggest a correlation between the areas in which phosphate ions are adsorbed and areas where akaganéite persists on the surface. In contrast, goethite (α-FeOOH) is a directly observed precursor of the hematite nanorods when 1,2-diamino propane is present. The PiFM data shows goethite in the center of the developing particles consistent with a mechanism in which the iron hydroxide re-dissolves and precipitates at the nanorod ends as hematite.
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Aug 2020
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B18-Core EXAFS
E01-JEM ARM 200CF
E02-JEM ARM 300CF
I11-High Resolution Powder Diffraction
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Liqun
Kang
,
Bolun
Wang
,
Qiming
Bing
,
Michal
Zalibera
,
Robert
Büchel
,
Ruoyu
Xu
,
Qiming
Wang
,
Yiyun
Liu
,
Diego
Gianolio
,
Chiu C.
Tang
,
Emma K.
Gibson
,
Mohsen
Danaie
,
Christopher
Allen
,
Ke
Wu
,
Sushila
Marlow
,
Ling-Dong
Sun
,
Qian
He
,
Shaoliang
Guan
,
Anton
Savitsky
,
Juan J.
Velasco-Vélez
,
June
Callison
,
Christopher W. M.
Kay
,
Sotiris E.
Pratsinis
,
Wolfgang
Lubitz
,
Jing-Yao
Liu
,
Feng Ryan
Wang
Diamond Proposal Number(s):
[15151, 15763, 16966, 17377, 19072, 19246, 20939, 17559, 24285, 19318, 19850]
Open Access
Abstract: Supported atomic metal sites have discrete molecular orbitals. Precise control over the energies of these sites is key to achieving novel reaction pathways with superior selectivity. Here, we achieve selective oxygen (O2) activation by utilising a framework of cerium (Ce) cations to reduce the energy of 3d orbitals of isolated copper (Cu) sites. Operando X-ray absorption spectroscopy, electron paramagnetic resonance and density-functional theory simulations are used to demonstrate that a [Cu(I)O2]3− site selectively adsorbs molecular O2, forming a rarely reported electrophilic η2-O2 species at 298 K. Assisted by neighbouring Ce(III) cations, η2-O2 is finally reduced to two O2−, that create two Cu–O–Ce oxo-bridges at 453 K. The isolated Cu(I)/(II) sites are ten times more active in CO oxidation than CuO clusters, showing a turnover frequency of 0.028 ± 0.003 s−1 at 373 K and 0.01 bar PCO. The unique electronic structure of [Cu(I)O2]3− site suggests its potential in selective oxidation.
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Aug 2020
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