B18-Core EXAFS
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Mei
Han
,
Jieshu
Zhou
,
Shaojun
Xu
,
Honggang
Sun
,
Xin
Zi
,
Ning
Wang
,
Jingrui
Han
,
Weijia
Zhou
,
Haibin
Wang
,
Kangning
Liu
,
Emiliano
Cortés
,
Songhua
Chen
,
Mingchuan
Luo
,
Jieqiong
Shan
,
Min
Liu
,
Ziyun
Wang
,
Hongyan
Liang
,
Yongchang
Liu
Diamond Proposal Number(s):
[19850]
Abstract: Neutral water electrolysis faces challenges due to insufficient OH− supply, which leads to inefficient oxygen evolution reaction (OER). Constructing a localized OH−-enriched reaction environment is crucial for enhancing the neutral OER activity. Here, an integrated catalyst design aimed at optimizing the local reaction environment is presented to improve catalytic activity. Specifically, a high-curvature needle morphology is constructed to strengthen the local electric field, which induces localized OH− accumulation and mitigates OH− deficiency in the neutral electrolyte. Moreover, implanting Ag cores not only improves the conductivity and long-term stability of the NiCo-based catalytic shells but also enables Ag diffusion to dope the catalytic layer. At the atomic scale, Ag dopants modify the activity of oxygen ligands and the polarity of metal-oxygen (M─O) bonds within the symmetric spinel structure. This modification facilitates surface reconstruction, resulting in the formation of a distorted Ag-O-Ni/Co-OH network. The elongation of the Ni/Co−O bond generates an inhomogeneous charge distribution that optimizes water polarization and deprotonation, accelerating water dissociation and *OH formation. The multiscale catalyst design results in a unique interface featuring a high-curvature surface and atomic-scale polarized M─O networks, synergistically enhancing local *OH accumulation. Therefore, the optimal Ag@NiCo2O4 catalyst delivers a η10 = 295 mV in an H-cell electrolyzer and 2.1 V @1 A cm−2 in a membrane electrode assembly electrolyzer. This finding provides a practical design for OER electrocatalysts in neutral electrolytes and opens a new avenue for optimizing catalytic performance by integrating multiple strategies.
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May 2025
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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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Fangfang
Peng
,
Bin
Zhang
,
Runyao
Zhao
,
Shiqiang
Liu
,
Yuxuan
Wu
,
Shaojun
Xu
,
Luke L.
Keenan
,
Huizhen
Liu
,
Qingli
Qian
,
Tianbin
Wu
,
Haijun
Yang
,
Zhimin
Liu
,
Jikun
Li
,
Bingfeng
Chen
,
Xinchen
Kang
,
Buxing
Han
Open Access
Abstract: Selective hydrogenolysis of biomass-derived furanic compounds is a promising approach for synthesizing aliphatic polyols by opening the furan ring. However, there remains a significant need for highly efficient catalysts that selectively target the Csp2–O bond in the furan ring, as well as for a deeper understanding of the fundamental atomistic mechanisms behind these reactions. In this study, we present the use of Pt–Fe bimetallic catalysts supported on layered double hydroxides [PtFex/LDH] for the hydrogenolysis of furanic compounds into aliphatic alcohols, achieving over 90% selectivity toward diols and triols. Our findings reveal that the synergy between Pt nanoparticles, atomically dispersed Pt sites and the support facilitates the formation of hydride-proton pair at the Ptδ+⋯O2− Lewis acid–base unit of PtFex/LDH through hydrogen spillover. The hydride specifically targets the Csp2–O bond in the furan ring, initiating an SN2 reaction and ring cleavage. Moreover, the presence of Fe improves the yield of desired alcohols by inhibiting the adsorption of vinyl groups, thereby suppressing the hydrogenation of the furan ring.
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Nov 2024
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I20-EDE-Energy Dispersive EXAFS (EDE)
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Donato
Decarolis
,
Monik
Panchal
,
Matthew
Quesne
,
Khaled
Mohammed
,
Shaojun
Xu
,
Mark
Isaacs
,
Adam H.
Clark
,
Luke L.
Keenan
,
Takuo
Wakisaka
,
Kohei
Kusada
,
Hiroshi
Kitagawa
,
C. Richard A.
Catlow
,
Emma K.
Gibson
,
Alexandre
Goguet
,
Peter
Wells
Diamond Proposal Number(s):
[21593]
Open Access
Abstract: Unravelling kinetic oscillations, which arise spontaneously during catalysis, has been a challenge for decades but is important not only to understand these complex phenomena but also to achieve increased activity. Here we show, through temporally and spatially resolved operando analysis, that CO oxidation over Rh/Al2O3 involves a series of thermal levering events—CO oxidation, Boudouard reaction and carbon combustion—that drive oscillatory CO2 formation. This catalytic sequence relies on harnessing localized temperature episodes at the nanoparticle level as an efficient means to drive reactions in situations in which the macroscopic conditions are unfavourable for catalysis. This insight provides a new basis for coupling thermal events at the nanoscale for efficient harvesting of energy and enhanced catalyst technologies.
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Jul 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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Jiangnan
Li
,
Xinran
Zhang
,
Mengtian
Fan
,
Yinlin
Chen
,
Yujie
Ma
,
Gemma
Smith
,
Inigo
Vitórica-Yrezábal
,
Daniel
Lee
,
Shaojun
Xu
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[34413]
Open Access
Abstract: Optimization of active sites and stability under irradiation are important targets for sorbent materials that might be used for iodine (I2) storage. Herein, we report the direct observation of I2 binding in a series of Cu(II)-based isostructural metal–organic frameworks, MFM-170, MFM-172, MFM-174, NJU-Bai20, and NJU-Bai21, incorporating various functional groups (–H, −CH3, – NH2, –C≡C–, and −CONH–, respectively). MFM-170 shows a reversible uptake of 3.37 g g–1 and a high packing density of 4.41 g cm–3 for physiosorbed I2. The incorporation of −NH2 and –C≡C– moieties in MFM-174 and NJU-Bai20, respectively, enhances the binding of I2, affording uptakes of up to 3.91 g g–1. In addition, an exceptional I2 packing density of 4.83 g cm–3 is achieved in MFM-174, comparable to that of solid iodine (4.93 g cm–3). In situ crystallographic studies show the formation of a range of supramolecular and chemical interactions [I···N, I···H2N] and [I···C≡C, I–C═C–I] between −NH2, –C≡C– sites, respectively, and adsorbed I2 molecules. These observations have been confirmed via a combination of solid-state nuclear magnetic resonance, X-ray photoelectron, and Raman spectroscopies. Importantly, γ-irradiation confirmed the ultraresistance of MFM-170, MFM-174, and NJU-Bai20 suggesting their potential as efficient sorbents for cleanup of radioactive waste.
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May 2024
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B18-Core EXAFS
I20-EDE-Energy Dispersive EXAFS (EDE)
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Khaled
Mohammed
,
Reza
Vakili
,
Donato
Decarolis
,
Shaojun
Xu
,
Luke L.
Keenan
,
Apostolos
Kordatos
,
Nikolay
Zhelev
,
Chris K.
Skylaris
,
Marina
Carravetta
,
Emma K.
Gibson
,
Haresh
Manyar
,
Alexandre
Goguet
,
Peter P.
Wells
Diamond Proposal Number(s):
[28666, 34632]
Open Access
Abstract: The need to achieve net zero requires decarbonisation across all areas of our industrialised society, including the production of chemicals. One example is the production of acetonitrile, which currently relies on fossil carbon. Recently, supported Pd nanoparticles have been shown to promote the selective transformation of bio-derived ethanol to acetonitrile. Elsewhere, current research has demonstrated the importance of interstitial structures of Pd in promoting specific transformations. In this study, we demonstrate through a spatially resolved operando energy-dispersive-EXAFS (EDE) technique that the selectivity to acetonitrile (up to 99%) is concurrent with the formation of a PdNx phase. This was evidenced from the features observed in the X-ray Absorption near edge structure validated against PdNx samples made via known synthesis methods. . Above 240 ℃, the Pd nanoparticles became progressively oxidised which led to the production of unwanted byproducts, primarily CO2. The spatially resolved analysis indicated that the Pd speciation was homogeneous across the catalyst profile throughout the series of studies performed. This work resolved the structural selectivity of Pd nanoparticles that directs ethanol ammoxidation towards acetonitrile, and provides important information on the performance descriptors required to advance this technology.
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Apr 2024
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
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Wenyaun
Huang
,
Qingqing
Mei
,
Shaojun
Xu
,
Bing
An
,
Meng
He
,
Jiangnan
Li
,
Yinlin
Chen
,
Xue
Han
,
Tian
Luo
,
Lixia
Guo
,
Joseph
Hurd
,
Daniel
Lee
,
Evan
Tillotson
,
Sarah
Haigh
,
Alex
Walton
,
Sarah
Day
,
Louise S.
Natrjan
,
Martin
Schroeder
,
Sihai
Yang
Open Access
Abstract: Formamides are important feedstocks for the manufacture of many fine chemicals. State-of-the-art synthesis of formamides relies on the use of an excess amount of reagents, giving copious waste and thus poor atom-economy. Here, we report the first example of direct synthesis of N-formamides by coupling two challenging reactions, namely reductive amination of carbonyl compounds, particularly biomass-derived aldehydes and ketones, and fixation of CO2 in the presence of H2 over a metal-organic framework supported ruthenium catalyst, Ru/MFM-300(Cr). Highly selective production of N-formamides has been observed for a wide range of carbonyl compounds. Synchrotron X-ray powder diffraction reveals the presence of strong host-guest binding interactions via hydrogen bonding and parallel-displaced π···π interactions between the catalyst and adsorbed substrates facilitating the activation of substrates and promoting selectivity to formamides. The use of multifunctional porous catalysts to integrate CO2 utilisation in the synthesis of formamide products will have a significant impact in the sustainable synthesis of feedstock chemicals.
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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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