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Instruments / Technical Area	Publication Details	Published
E01-JEM ARM 200CF	Developing Silicalite-1 encapsulated Ni nanoparticles as sintering-/coking-resistant catalysts for dry reforming of methane 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 Chemical Engineering Journal 5 DOI: 10.1016/j.cej.2022.137439 Diamond Proposal Number(s): [29468] Open Access Show Abstract ▼ 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.	Jun 2022
B22-Multimode InfraRed imaging And Microspectroscopy	On understanding the sequential post-synthetic microwave-assisted dealumination and alkaline treatment of Y zeolite Rongxin Zhang , Run Zou , Wei Li , Yabin Chang , Xiaolei Fan Microporous And Mesoporous Materials 270 DOI: 10.1016/j.micromeso.2022.111736 Diamond Proposal Number(s): [22476] Show Abstract ▼ Abstract: Systematic investigation was performed to understand the change of physiochemical properties in Y zeolite after the microwave (MW)-assisted dealumination (using mineral acid, HCl, and chelating agent, EDTA4−) and the subsequent alkaline treatment (of the dealuminated zeolites). The findings show that the combination of EDTA4− and hydrogen ions was effective to achieve dealumination of zeolite Y under MW irradiation, which formed complexed framework Al, instead of extra-framework Al (EFAl), to be extracted readily by the sequential alkaline treatment for mesopore formation. Conversely, under the same MW condition, the use of HCl encouraged the formation of EFAl species in the defective Y framework, which did not benefit the mesopore formation. The disclose of the distinct dealumination mechanisms of the MW-assisted method using different agents can benefit the further development of effective MW methods for dealumination of zeolites and/or making mesoporous zeolites.	Feb 2022
B18-Core EXAFS	Palladium-doped hierarchical ZSM-5 for catalytic selective oxidation of allylic and benzylic alcohols Shengzhe Ding , Muhammad Ganesh , Yilai Jiao , Xiaoxia Ou , Mark Isaacs , Mark S'Ari , Antonio Torres Lopez , Xiaolei Fan , Christopher M. A. Parlett Royal Society Open Science 8 DOI: 10.1098/rsos.211086 Diamond Proposal Number(s): [15151] Open Access Show Abstract ▼ Abstract: Hierarchical zeolites have the potential to provide a breakthrough in transport limitation, which hinders pristine microporous zeolites and thus may broaden their range of applications. We have explored the use of Pd-doped hierarchical ZSM-5 zeolites for aerobic selective oxidation (selox) of cinnamyl alcohol and benzyl alcohol to their corresponding aldehydes. Hierarchical ZSM-5 with differing acidity (H-form and Na-form) were employed and compared with two microporous ZSM-5 equivalents. Characterization of the four catalysts by X-ray diffraction, nitrogen porosimetry, NH3 temperature-programmed desorption, CO chemisorption, high-resolution scanning transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy allowed investigation of their porosity, acidity, as well as Pd active sites. The incorporation of complementary mesoporosity, within the hierarchical zeolites, enhances both active site dispersion and PdO active site generation. Likewise, alcohol conversion was also improved with the presence of secondary mesoporosity, while strong Brønsted acidity, present solely within the H-form systems, negatively impacted overall selectivity through undesirable self-etherification. Therefore, tuning support porosity and acidity alongside active site dispersion is paramount for optimal aldehyde production.	Oct 2021
I20-EDE-Energy Dispersive EXAFS (EDE)	Electrochemical Redox Couples: A Combined XAS and Modulation excitation study Armando Ibraliu , Xiaolei Fan , Luke Keenan , Daniel Bowron , Sofia Diaz-Moreno , Chris Hardacre XAFS2021 Show Abstract ▼ Abstract: The use of X-ray absorption spectroscopy (XAS) to follow liquid phase catalysed reactions is widely used. However, in catalysis, small quantities of active species are usually present, complicating the differentiation of spectator and active species. In these cases, the use of Modulation Excitation (ME) techniques can be used to achieve a better signal-to-noise ratio by cycle averaging. ME coupled with phase-sensitive detection can significantly improve the sensitivity of the spectroscopic technique by filtering out contributions of spectator species that are unaltered by the external stimulation. This has been used in combined XAS/DRIFTS studies of gas phase reactions, successfully identifying surface intermediates present in small concentration. [1] In this study, ME assisted by phase-sensitive detection analysis has been applied to the study of liquid-phase reactions using XAS. This methodology has been successfully applied to the study of the electrochemical oxidation of Na4FeII(CN)6. The experiment was undertaken in a newly three-electrode designed electrochemical cell at the I20-EDE beamline at Diamond Light Source. 30, 50, and 75 mM aqueous solutions of the iron complex in 1 M NaF/NaCl electrolytes were investigated. Cyclic voltammograms were measured during potential cycling with potential limits ± 1.5 V, at 200 and 300 mV/s scan rates, for 100 cycles. This perturbed the system reversibly allowing the cycle averaging of the XAS data. This study shows that ME assisted by phase-sensitive detection analysis can be successfully applied to XAS for the study of liquid-phase reactions. Signal-to-noise ratios were improved significantly through cycle averaging, and additional information were extracted from the phase-resolved FT-EXAFS spectra demonstrating the enhanced sensitivity.	Jul 2021
	Recent developments in multifunctional catalysts for fatty acid hydrodeoxygenation as a route towards biofuels Shengzhe Ding , Christopher M. A. Parlett , Xiaolei Fan Molecular Catalysis 42 DOI: 10.1016/j.mcat.2021.111492 Show Abstract ▼ Abstract: Catalytic hydrodeoxygenation (HDO) provides a promising route for upgrading biomass-derived fatty acids to alkanes, which are potential biofuels (e.g. jet fuel (C8–C16) and diesel (C12–C22)) that could reduce our reliance on unsustainable fossil fuels. Currently, catalytic HDO, conducted over catalysts such as molybdenum disulfide, necessitates harsh operating conditions (>300 °C) which is both environmentally and economically unsustainable and promotes unwanted side reactions, e.g. cracking, which compromises product selectivity. Accordingly, the development of novel catalysts, which enable efficient and sustainable HDO, under milder operating conditions, and their translation from lab bench to large-scale production are highly desired. This review discusses the recent development of heterogeneous catalysts for HDO (including reaction pathways, mechanisms, and side reactions) and explores design strategies for the development of new multifunctional catalysts with potential to enable future development of HDO processes under mild conditions. In particular, we consider the sequential cascade transformation of fatty acids into fatty alcohols (via hydrodeoxygenation) and then hydrocarbons (via dehydration and hydrogenation), which requires the coupling of different but complementary catalytic sites, as an attractive alternative mild HDO strategy.	Mar 2021
	An efficient microwave-assisted chelation (MWAC) post-synthetic modification method to produce hierarchical Y zeolites Samer Abdulridha , Rongxin Zhang , Shaojun Xu , Aleksander Tedstone , Xiaoxia Ou , Jiacheng Gong , Boyang Mao , Mark Frogley , Carlo Bawn , Zhaoxia Zhou , Xinran Zhang , Sarayute Chansai , Stuart M. Holmes , Christopher Hardacre , Arthur A. Garforth , Sihai Yang , Yilai Jiao , Xiaolei Fan Microporous And Mesoporous Materials 311 DOI: 10.1016/j.micromeso.2020.110715 Show Abstract ▼ Abstract: We report a low-cost, highly energy efficient microwave-assisted chelation (MWAC) method, which enabled the post-synthetic modification of synthetic zeolites for adopting hierarchical structures within minutes. Exemplified by Zeolite Y, hierarchical Y zeolites prepared in this way showed exceptional specific external surface areas of >300 m2 g−1 and mesopore volumes of >0.46 cm3 g−1. Comparative assessments revealed that developed zeolites have shown significantly improved catalytic activities for catalysis involving large substrates, such as catalytic cracking and hydrocracking of plastics.	Oct 2020
E01-JEM ARM 200CF	PtNi bimetallic structure supported on UiO-67 metal-organic framework (MOF) during CO oxidation Reza Vakili , Thomas J. A. Slater , Christopher Hardacre , Alex S. Walton , Xiaolei Fan Journal Of Catalysis DOI: 10.1016/j.jcat.2020.09.013 Diamond Proposal Number(s): [23221] Open Access Show Abstract ▼ Abstract: Supported bimetallic nanoparticles (BNPs) are promising catalysts, but study on their compositional and structural changes under reaction conditions remains a challenge. In this work, the structure of PtNi BNPs supported on UiO-67 metal-organic framework (MOF) catalyst (i.e., PtNi@UiO-67) was investigated by in situ by near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS). The results showed differences in the reduction behaviour of Ni species in PtNi BNPs and monometallic Ni supported on UiO-67 catalysts (i.e., PtNi@UiO-67 and Ni@UiO-67), suggesting charge transfer between metallic Pt and Ni oxides in PtNi@UiO-67. Under CO oxidation conditions, Ni oxides segregated to the outer surface of the BNPs forming a thin layer of NiOx on top of the metallic Pt (i.e., a NiOx-on-Pt structure). This resulted in a core-shell structure which was confirmed by high-resolution scanning transmission electron microscopy (HR-STEM). Accordingly, the layer of NiOx on PtNi BNPs, which is stabilised by charge transfer from metallic Pt, was proposed as the possible active phase for CO oxidation, being responsible for the enhanced catalytic activity observed in the bimetallic PtNi@UiO-67 catalyst.	Sep 2020
I11-High Resolution Powder Diffraction	C2H4 and C2H6 adsorption-induced structural variation of pillared-layer CPL-2 MOF: A combined experimental and Monte Carlo simulation study Huan Xiang , Joseph H. Carter , Chiu C. Tang , Claire A. Murray , Sihai Yang , Xiaolei Fan , Flor R. Siperstein Chemical Engineering Science DOI: 10.1016/j.ces.2020.115566 Diamond Proposal Number(s): [22138] Show Abstract ▼ Abstract: Coordination pillared-layer metal-organic frameworks (CPL-MOFs), such as CPL-2, are interesting versatile and porous materials with the potential for gas adsorption and separation. CPL-2 shows the unusual and gradual linker rotation upon the adsorption of ethylene (C2H4) and ethane (C2H6), leading to a fully reversible adsorption isotherm specifically under the conditions studied. Grand canonical Monte Carlo (GCMC) simulations showed that it is impossible to accommodate the experimentally observed loadings of C2H4 and C2H6 in CPL-2 using the crystallographic structure reported in the literature. According to the simulation findings, the pore expansion might be initiated by the clockwise 4,4′-bipyridine (bpy) pillar linker rotation. The pillar rotation leads to the enlarged pore volume, rendering additional adsorption sites, which are not present in the pristine structure. In situ synchrotron PXRD experiments for C2H4 and C2H6 adsorption on CPL-2 confirmed the occurrence of pore expansion in CPL-2 MOF. The combined experimental and simulation study shows for the first time that the linker rotation in CPL-2 can result in a adsorption isotherm without hysteresis. This work developed a real insight into the nature of pillared-layer MOFs, and the revealed structural changes could be potentially exploited to enhance alkene and alkane working capacities of such microporous materials.	Feb 2020
B18-Core EXAFS	Understanding the CO oxidation on Pt nanoparticles supported on MOFs by operando XPS Xiaolei Fan , Reza Vakili , Emma Gibson , Sarayute Chansai , Shaojun Xu , Peter Wells , Christopher Hardacre , Alex Walton , Nadeen Al-Janabi Chemcatchem DOI: 10.1002/cctc.201801067 Diamond Proposal Number(s): [8071] Open Access Show Abstract ▼ Abstract: Metal‐organic frameworks (MOFs) are playing a key role in developing the next generation of heterogeneous catalysts. In this work, near ambient pressure X‐ray photoelectron spectroscopy (NAP‐XPS) is applied to study in operando the CO oxidation on Pt@MOFs (UiO‐67) and Pt@ZrO2 catalysts, revealing the same Pt surface dynamics under the stoichiometric CO/O2 ambient at 3 mbar. Upon the ignition at ca. 200°C, the signature Pt binding energy (BE) shift towards the lower BE (from 71.8 to 71.2 eV) is observed for all catalysts, confirming metallic Pt nanoparticles (NPs) as the active phase. Additionally, the plug‐flow light‐off experiments show the superior activity of the Pt@MOFs catalyst in CO oxidation than the control Pt@ZrO2 catalyst with ca. 28% drop in the T50% light‐off temperature, as well as high stability, due to their sintering‐resistance feature. These results provide evidence that the uniqueness of MOFs as the catalyst supports lies in the structural confinement effect.	Jul 2018

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