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Dive into the research topics where Donglong Fu is active.

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Featured researches published by Donglong Fu.


Angewandte Chemie | 2016

Coke Formation in a Zeolite Crystal During the Methanol-to- Hydrocarbons Reaction as Studied with Atom Probe Tomography

Joel E. Schmidt; Jonathan D. Poplawsky; Baishakhi Mazumder; Özgün Attila; Donglong Fu; D. A. Matthijs de Winter; Florian Meirer; Simon R. Bare; Bert M. Weckhuysen

Abstract Understanding the formation of carbon deposits in zeolites is vital to developing new, superior materials for various applications, including oil and gas conversion processes. Herein, atom probe tomography (APT) has been used to spatially resolve the 3D compositional changes at the sub‐nm length scale in a single zeolite ZSM‐5 crystal, which has been partially deactivated by the methanol‐to‐hydrocarbons reaction using 13C‐labeled methanol. The results reveal the formation of coke in agglomerates that span length scales from tens of nanometers to atomic clusters with a median size of 30–60 13C atoms. These clusters correlate with local increases in Brønsted acid site density, demonstrating that the formation of the first deactivating coke precursor molecules occurs in nanoscopic regions enriched in aluminum. This nanoscale correlation underscores the importance of carefully engineering materials to suppress detrimental coke formation.


Angewandte Chemie | 2016

Template-Framework Interactions in Tetraethylammonium-Directed Zeolite Synthesis.

Joel E. Schmidt; Donglong Fu; Michael W. Deem; Bert M. Weckhuysen

Abstract Zeolites, having widespread applications in chemical industries, are often synthesized using organic templates. These can be cost‐prohibitive, motivating investigations into their role in promoting crystallization. Herein, the relationship between framework structure, chemical composition, synthesis conditions and the conformation of the occluded, economical template tetraethylammonium (TEA+) has been systematically examined by experimental and computational means. The results show two distinct regimes of occluded conformer tendencies: 1) In frameworks with a large stabilization energy difference, only a single conformer was found (BEA, LTA and MFI). 2) In the frameworks with small stabilization energy differences (AEI, AFI, CHA and MOR), less than the interconversion of TEA+ in solution, a heteroatom‐dependent (Al, B, Co, Mn, Ti, Zn) distribution of conformers was observed. These findings demonstrate that host–guest chemistry principles, including electrostatic interactions and coordination chemistry, are as important as ideal pore‐filling.


Microscopy and Microanalysis | 2017

Nanoscale Chemical Imaging of Coking Mechanisms in a Zeolite ZSM-5 Crystal by Atom Probe Tomography

Jonathan D. Poplawsky; Joel E. Schmidt; Baishakhi Mazumder; Wei Guo; Özgün Attila; Donglong Fu; D. A. Matthijs de Winter; Florian Meirer; Simon R. Bare; Bert M. Weckhuysen

Zeolites are crystalline microporous materials that are used in large quantities as solid catalysts in oil refining and automotive emission treatments. Due to their widespread use there is much effort to improve their catalytic performance, including activity, selectivity and stability. Coking is known to be a main mechanism for the degradation of zeolite ZSM-5 during reactions with carbon-containing substances, such as methanol. Understanding the nanoscale chemical distribution, such as the location of coke species leading to catalyst deactivation, within zeolites has been a major challenge due to the difficulty in detection of carbon species and electron beam sensitivity when using transmission electron microscopy based techniques. Atom probe tomography (APT) has recently been demonstrated as a useful characterization technique to understand the nanoscale elemental distribution within zeolite materials, allowing for the direct identification of chemical segregation during the processing and reaction of zeolite catalysts. [1-3]


Angewandte Chemie | 2017

Highly Oriented Growth of Catalytically Active Zeolite ZSM-5 Films with a Broad Range of Si/Al Ratios

Donglong Fu; Joel E. Schmidt; Zoran Ristanović; Abhishek Dutta Chowdhury; Florian Meirer; Bert M. Weckhuysen

Abstract Highly b‐oriented zeolite ZSM‐5 films are critical for applications in catalysis and separations and may serve as models to study diffusion and catalytic properties in single zeolite channels. However, the introduction of catalytically active Al3+ usually disrupts the orientation of zeolite films. Herein, using structure‐directing agents with hydroxy groups, we demonstrate a new method to prepare highly b‐oriented zeolite ZSM‐5 films with a broad range of Si/Al ratios (Si/Al=45 to ∞). Fluorescence micro‐(spectro)scopy was used to monitor misoriented microstructures, which are invisible to X‐ray diffraction, and show Al3+ framework incorporation and illustrate the differences between misoriented and b‐oriented films. The methanol‐to‐hydrocarbons process was studied by operando UV/Vis diffuse reflectance micro‐spectroscopy with on‐line mass spectrometry, showing that the b‐oriented zeolite ZSM‐5 films are active and stable under realistic process conditions.


ChemPhysChem | 2018

Diagnosing the Internal Architecture of Zeolite Ferrierite

Joel E. Schmidt; Frank C. Hendriks; Martin Lutz; L. Christiaan Post; Donglong Fu; Bert M. Weckhuysen

Abstract Large crystals of zeolite ferrierite (FER) are important model systems for spatially resolved catalysis and diffusion studies, though there is considerable variation in crystal habit depending on the chemical composition and employed synthesis conditions. A synergistic combination of techniques has been applied, including single crystal X‐ray diffraction, high‐temperature in situ confocal fluorescence microscopy, fluorescent probe molecules, wide‐field microscopy and atomic force microscopy to unravel the internal architecture of three distinct FER zeolites. Pyrolyzed template species can be used as markers for the 8‐membered ring direction as they are trapped in the terraced roof of the FER crystals. This happens as the materials grow in a layer‐by‐layer, defect‐free manner normal to the large crystal surface, and leads to a facile method to diagnose the pore system orientation, which avoids tedious single crystal X‐ray diffraction experiments.


Journal of the American Chemical Society | 2018

Isolating Clusters of Light Elements in Molecular Sieves with Atom Probe Tomography

Joel E. Schmidt; Linqing Peng; Alessandra Lucini Paioni; Helena Leona Ehren; Wei Guo; Baishakhi Mazumder; D. A. Matthijs de Winter; Özgün Attila; Donglong Fu; Abhishek Dutta Chowdhury; Klaartje Houben; Marc Baldus; Jonathan D. Poplawsky; Bert M. Weckhuysen

Understanding the 3-D distribution and nature of active sites in heterogeneous catalysts is critical to developing structure–function relationships. However, this is difficult to achieve in microporous materials as there is little relative z-contrast between active and inactive framework elements (e.g., Al, O, P, and Si), making them difficult to differentiate with electron microscopies. We have applied atom probe tomography (APT), currently the only nanometer-scale 3-D microscopy to offer routine light element contrast, to the methanol-to-hydrocarbons (MTH) catalyst SAPO-34, with Si as the active site, which may be present in the framework as either isolated Si species or clusters (islands) of Si atoms. 29Si solid-state NMR data on isotopically enriched and natural abundance materials are consistent with the presence of Si islands, and the APT results have been complemented with simulations to show the smallest detectable cluster size as a function of instrument spatial resolution and detector efficiency. We have identified significant Si–Si affinity in the materials, as well as clustering of coke deposited by the MTH reaction (13CH3OH used) and an affinity between Brønsted acid sites and coke. A comparison with simulations shows that the ultimate spatial resolution that can be attained by APT applied to molecular sieves is 0.5–1 nm. Finally, the observed 13C clusters are consistent with hydrocarbon pool mechanism intermediates that are preferentially located in regions of increased Brønsted acidity.


Chemical Communications | 2017

Nanoscale infrared imaging of zeolites using photoinduced force microscopy

Donglong Fu; Katie Park; Guusje Delen; Özgün Attila; Florian Meirer; Derek Nowak; Sung Park; Joel E. Schmidt; Bert M. Weckhuysen


ChemPhysChem | 2018

Cover Feature: Diagnosing the Internal Architecture of Zeolite Ferrierite (ChemPhysChem 4/2018)

Joel E. Schmidt; Frank C. Hendriks; Martin Lutz; L. Christiaan Post; Donglong Fu; Bert M. Weckhuysen


Angewandte Chemie | 2018

Uniformly Oriented Zeolite ZSM-5 Membranes with Tunable Wettability on a Porous Ceramic

Donglong Fu; Joel E. Schmidt; Paul Pletcher; Pelin Karakiliç; Xinwei Ye; Carolien M. Vis; Pieter C. A. Bruijnincx; Matthias Filez; Laurens D. B. Mandemaker; Louis Winnubst; Bert M. Weckhuysen


ACS Catalysis | 2018

Deconvoluting the Competing Effects of Zeolite Framework Topology and Diffusion Path Length on Methanol-to-Hydrocarbon Reactions

Yufeng Shen; Thuy T. Le; Donglong Fu; Joel E. Schmidt; Matthias Filez; Bert M. Weckhuysen; Jeffrey D. Rimer

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Baishakhi Mazumder

Oak Ridge National Laboratory

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Jonathan D. Poplawsky

Oak Ridge National Laboratory

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Abhishek Dutta Chowdhury

Indian Institute of Technology Bombay

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