Creation of Exclusive Artificial Cluster Defects by Selective Metal Removal in the (Zn, Zr) Mixed-Metal UiO-66

Feng, Xiao; Jena, Himanshu Sekhar; Krishnaraj, Chidharth; Esteban, Daniel Arenas; Leus, Karen; Wang, Guangbo; Sun, Jiamin; Rüscher, Martina; Timoshenko, Janis; Cuenya, Beatriz Roldán; Bals, Sara; Voort, Pascal Van Der

doi:10.1021/jacs.1c05357

Cited by 69 publications

(30 citation statements)

References 30 publications

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“…In general, the second step can be attributed to the defects degree, [16] which was supported by mass spectrometry of the original and 330 °C heated MIL‐88B‐NS40 (Figure S5). In addition, the highest peak in DTG curves and the largest weight loss from 150 to 330 °C (Table S2) imply the existence of the maximum defects in the MIL‐88‐NS40 [17] . The nitrogen adsorption and desorption isotherms exhibit that the samples own the microporous structures (Figure S6).…”

Section: Resultsmentioning

confidence: 97%

Designing Heteroatom‐Codoped Iron Metal–Organic Framework for Promotional Photoreduction of Carbon Dioxide to Ethylene

Guo

Yang

et al. 2023

Angew Chem Int Ed

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Rational engineering active sites and vantage defects of catalysts are promising but grand challenging task to enhance photoreduction CO2 to high value‐added C2 products. In this study, we designed an N,S‐codoped Fe‐based MIL‐88B catalyst with well‐defined bipyramidal hexagonal prism morphology via a facile and effective process, which was synthesized by addition of appropriate 1,2‐benzisothiazolin‐3‐one (BIT) and acetic acid to the reaction solution. Under simulated solar irradiation, the designed catalyst exhibits high C2H4 evolution yield of 17.7 μmol g−1⋅h, which has been rarely achieved in photocatalytic CO2 reduction process. The synergistic effect of Fe‐N coordinated sites and reasonable defects in the N,S‐codoped photocatalyst can accelerate the migration of photogenerated carriers, resulting in high electron density, and this in turn helps to facilitate the formation and dimerization of C−C coupling intermediates for C2H4 effectively.

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Section: Resultsmentioning

confidence: 97%

Designing Heteroatom‐Codoped Iron Metal–Organic Framework for Promotional Photoreduction of Carbon Dioxide to Ethylene

Guo

Yang

et al. 2023

Angew Chem Int Ed

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“…For UiO-66, a defect concentration of 0.1 has been widely reported experimentally in defect engineering studies, with concentrations up to 0.15 or even 0.4 also being reported with some unconventional synthesis routes. 24,36,37 In these studies, no peak splits or shifts are observed for defective MOFs, but surface area changes of as high as 20% were reported. Our results in Figure 2b illustrate that having defect concentrations as high as 0.25 introduces minimal changes in the PXRD pattern and surface area, which is consistent with the experimental observation.…”

mentioning

confidence: 88%

Efficient Generation of Large Collections of Metal–Organic Framework Structures Containing Well-Defined Point Defects

Jamdade

et al. 2023

J. Phys. Chem. Lett.

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High-throughput molecular simulations of metal−organic frameworks (MOFs) are a useful complement to experiments to identify candidates for chemical separation and storage. All previous efforts of this kind have used simulations in which MOFs are approximated as defect-free. We introduce a tool to readily generate missing-linker defects in MOFs and demonstrate this tool with a collection of 507 defective MOFs. We introduce the concept of the maximum possible defect concentration; at higher defect concentrations, deviations from the defect-free crystal structure would be readily evident experimentally. We studied the impact of defects on molecular adsorption as a function of defect concentrations. Defects have a slightly negative or negligible influence on adsorption at low pressures for ethene, ethane, and CO 2 but a strong positive influence for methanol due to hydrogen bonding with defects. Defective structures tend to have loadings slightly higher than those of defect-free structures for all adsorbates at elevated pressures.

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“…Third, unlike HAADF-STEM that only favors high- Z elements, iDPC-STEM can be used to simultaneously image heavy and light elements. Owing to these features, iDPC-STEM has emerged as a powerful tool for imaging beam-sensitive materials. ,,,− For example, atomic-resolution iDPC-STEM images of MOFs have been successfully acquired, in which the metal clusters and the organic linkers in the structures can both be clearly identified without image processing, except applying a high-pass filter to improve the SNR (Figure ).…”

Section: Idpc-stem and 4d-stemmentioning

confidence: 99%

Low-Dose Electron Microscopy Imaging of Electron Beam-Sensitive Crystalline Materials

Zhang

et al. 2022

Acc. Mater. Res.

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Conspectus As one of the most widely used characterization tools in materials science, (scanning) transmission electron microscopy ((S)TEM) has the unique ability to directly image specimens with atomic resolution. Compared to diffraction-based techniques, the main advantage of (S)TEM imaging is that in addition to the periodic average structures of crystalline materials, it can be used to probe nonperiodic local structures such as surfaces, interfaces, dopants, and defects, which have crucial impacts on material properties. However, many crystalline materials are extremely sensitive to electron beam irradiation, which can only withstand dozens (or even fewer) of electrons per square angstrom before they undergo structural damage. Although using electron doses lower than the thresholds can in principle preserve their structures, the thus acquired images are too noisy to be useful. Consequently, high-resolution imaging of the inherent structures of such electron beam-sensitive materials using (S)TEM is a long-standing challenge. In recent years, the advances in electron detectors and image-acquisition methods have enabled high-resolution (S)TEM with ultralow electron doses, largely overcoming this challenge. A series of highly electron beam-sensitive materials that are traditionally considered impossible to be imaged with (S)TEM, including metal organic frameworks (MOFs), covalent organic frameworks (COFs), organic–inorganic hybrid halide perovskites, and supramolecular crystals, have been successfully imaged at atomic resolutions. This technological advance has greatly expanded the application range of electron microscopy. This Account focuses on our recent works pertaining to the high-resolution imaging of electron beam-sensitive materials using very low electron doses. We first explain that the use of direct-detection electron-counting (DDEC) cameras provides the hardware basis for successful low-dose high-resolution TEM (HRTEM). Subsequently, we introduce a suite of methods to address the challenges peculiar to low-dose HRTEM, including rapid search for crystal zone axes, precise alignment of the image stack, and accurate determination of the defocus value. These methods, combined with the use of a DDEC camera, ensure efficient imaging of electron beam-sensitive crystalline materials in the TEM mode. Moreover, we demonstrate that integrated differential phase contrast STEM (iDPC-STEM) is an effective method for acquiring directly interpretable atomic-resolution images under low-dose conditions. In addition, we share our views on the great potential of four-dimensional STEM (4D-STEM) in imaging highly electron beam-sensitive materials and provide preliminary simulation results to demonstrate its feasibility. Finally, we discuss the significance of developing (S)TEM specimen preparation techniques applicable for sensitive materials and the advantages of using the cryogenic focused ion beam (cryo-FIB) technique for this purpose.

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Creation of Exclusive Artificial Cluster Defects by Selective Metal Removal in the (Zn, Zr) Mixed-Metal UiO-66

Cited by 69 publications

References 30 publications

Designing Heteroatom‐Codoped Iron Metal–Organic Framework for Promotional Photoreduction of Carbon Dioxide to Ethylene

Designing Heteroatom‐Codoped Iron Metal–Organic Framework for Promotional Photoreduction of Carbon Dioxide to Ethylene

Efficient Generation of Large Collections of Metal–Organic Framework Structures Containing Well-Defined Point Defects

Low-Dose Electron Microscopy Imaging of Electron Beam-Sensitive Crystalline Materials

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