Figure - available from: Particle & Particle Systems Characterization
This content is subject to copyright. Terms and conditions apply.
The scheme for continuous adjustment of collection angle. a) Convergence semi‐angle α is smaller than inner collection angle β. b) Convergence semi‐angle α equals collection angle β. c) Convergence semi‐angle α is bigger than collection angle β. d) Collection angle β can be changed by adjusting IL3 in combination with camera length.
Source publication
![ADF‐STEM images of MFI zeolite taken along the [010] incidence with...](publication/364939447/figure/fig3/AS:11431281244632786@1715957664767/ADF-STEM-images-of-MFI-zeolite-taken-along-the-010-incidence-with-different-convergence_Q320.jpg)
It has become very important to study and find optimal conditions for imaging electron‐beam (e‐beam) sensitive materials in scanning transmission electron microscopy under low electron‐dose with high signal‐to‐noise ratio (SNR). Convergence and collection angles and electron‐probe current are essential parameters. However, these parameters have rar...
Similar publications
Recent advancements in electron detectors and computing power have revolutionized the rapid recording of millions of 2D diffraction patterns across a grid of probe positions, known as four-dimensional scanning transmission electron microscopy (4D-STEM). These datasets serve as the foundation for innovative STEM imaging techniques like integrated ce...
Precise monitoring of fluid flow rates constitutes an integral problem in various lab-on-a-chip applications. While off-chip flow sensors are commonly used, new sensing mechanisms are being investigated to address the needs of increasingly complex lab-on-a-chip platforms which require local and non-intrusive flow rate sensing. In this regard, the d...
Understanding the optoelectronic properties of optically active materials at the nanoscale often proves challenging due to the diffraction-limited resolution of visible light probes and the dose sensitivity of many optically active materials to high-energy electron probes. In this study, we demonstrate correlative synchrotron-based scanning X-ray E...
![Figure 1: (a) Simplified tectonic map of China [51]. (b) Geological map...](publication/373744794/figure/fig1/AS:11431281187162239@1694135903839/a-Simplified-tectonic-map-of-China-51-b-Geological-map-of-Longhua-chalcedony_Q320.jpg)
A low-crystallinity index chalcedony was found in the rhyolitic ignimbrite of the Late Jurassic Zhangjiakou Formation, located in Longhua County, Hebei Province, China. This chalcedony occurs as fillings along the fragile fractures of the host rock and is distinct from any other chalcedony deposits, such as the known basalt and carbonate-related ty...
В статье представлены анализ и результаты научных исследований техногенных шлаковых отходов свинцового производства. После закрытия и ликвидации завода, оставшиеся отходы, в виде шлаков, являются источником экологического загрязнения почвы, грунтовых вод и воздуха. Шлаки свинцового производства содержат большое количество токсичных соединений, таки...
Citations
... High SNR ADF-STEM images were captured on a JEM-ARM300F GRAND ARM (JEOL, Tokyo, Japan) aberration-corrected scanning transmission electron microscope equipped with double aberration correctors with an operating voltage of 300 kV and camera length of 800 mm. Image acquisition according to methods reported in the literature was conducted with a semi-angle of 10 mard, collection angles of 10-40 mard and an electron dose of 2653 e − /Å 2 [37]. High-resolution transmission electron microscope photographs (HR-TEM) were obtained and selected-area electron diffraction (SAED) and elemental analysis (EDX) were performed using the Tecnai G2 F20 S-Twin (FEI, Hillsboro, OR, USA) field emission transmission electron microscope operated at 200 kV and equipped with an Oxford Instruments X-Max 80T EDS (Oxford Instruments, Abingdon, Oxfordshire, UK) probe. ...
... Figure 9 shows the High SNR ADF-STEM results for CuZn@ZSM-5. The atomic -resolution image and intensity analysis provides actual spatial evidence of the zeolite framework with metal atoms in the channels [26,37]. The metal atoms in the channels of the MFI framework are directly visualized along the [010] zone axis as Figure 9a. ...
... Among them, position 1# is an empty channel, and the diameter of the hole is 5-6 Å which is consistent Figure 9 shows the High SNR ADF-STEM results for CuZn@ZSM-5. The atomic -resolution image and intensity analysis provides actual spatial evidence of the zeolite framework with metal atoms in the channels [26,37]. The metal atoms in the channels of the MFI framework are directly visualized along the [010] zone axis as Figure 9a. ...
CuZn-based catalysts are widely used in CO2 hydrogenation, which may effectively convert CO2 to methanol and alleviate CO2 emission issues. The precise design of a model catalyst with a clear atomic structure is crucial in studying the relationship between structure and catalytic activity. In this work, a one-pot strategy was used to synthesize CuZn@ZSM-5 catalysts with approximately two Cu atoms and one Zn atom per unit cell. Atomic Cu and Zn species are confirmed to be located in the [54.6.102] and [62.104] tilings, respectively, by using magic-angle spinning nuclear magnetic resonance spectroscopy (MAS NMR), synchrotron X-ray powder diffraction (SXRD) and high-signal-to-noise-ratio annular dark field scanning transmission electron microscopy (High SNR ADF-STEM). Catalytic hydrogenation of CO2 to methanol was used as a model reaction to investigate the activity of the catalyst with confined active species. Compared to the Cu@ZSM-5, Zn@ZSM-5 and their mixture, the CuZn@ZSM-5 catalyst with a close Cu–Zn distance of 4.5 Å achieves a comparable methanol space–time yield (STY) of 92.0 mgmethanol·gcatal−1·h−1 at 533 K and 4 MPa with high stability. This method is able to confine one to three metal atoms in the zeolite channel and avoid migration and agglomeration of the atoms during the reaction, which maintains the stability of the catalyst and provides an efficient way for adjustment of the type and number of metal atoms along with the distances between them in zeolites.
Zeolites are among the most important heterogeneous catalysts, widely employed in separation reaction, fine chemical production, and petroleum refining. Through rational design of the frameworks, zeolites with versatile functions can be synthesized. Local imaging of zeolite structures at the atomic scale, including the basic framework atoms (Si, Al, and O) and extra-framework cations, is necessary to understand the structure-function relationship of zeolites. Herein, we implemented electron ptychography into direct imaging of local structures of two zeolites, Na-LTA and ZSM-5. Not only all the framework atoms but also extra-framework Na+ cations with only 1/4 occupation probabilities in Na-LTA were directly observed. Local structures of ZSM-5 zeolites having guest molecules among channels with different orientations were also unraveled using different reconstruction algorithms. The approach presented here provides a new way to locally image zeolites structure, and it is expected to be an essential key for further studying and tuning zeolites active sites at the atomic level.
