Introducing and Controlling Water Vapor in Closed-Cell <i>In Situ</i> Electron Microscopy Gas Reactions

Unocic, Kinga A.; Walden, Franklin S.; Marthe, N. L.; Datye, Abhaya K.; Bigelow, Wilbur C.; Allard, Lawrence F.

doi:10.1017/s1431927620000185

Cited by 17 publications

(16 citation statements)

References 45 publications

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“…Furthermore, in a recent development, an in situ gas-phase TEM was coupled to an online mass spectrometer (MS) for analysis of trace amounts of a variety of gas products (ppm-level), which can be tremendously valuable for many electrocatalytic reactions, such as the electrochemical reduction of CO 2 or N 2 , as well as the oxidation of alcohols or NH 3 , etc. Figure I,J features a very recent study by Unocic et al on a model system of cubic MgO crystals and their transition to Mg(OH) 2 under controlled relative humidity (RH%) and temperatures . The RH% could be adjusted from 2% up to 100% at a pressure of ∼17 Torr, and the temperature could be controlled from 25 up to 900 °C in the presence of water vapor.…”

Section: Scanning and Transmission Electron Microscopy (Stem)mentioning

confidence: 93%

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OperandoMethods in Electrocatalysis

et al. 2021

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Electrocatalysis has been the cornerstone for enhancing energy efficiency, minimizing environmental impacts and carbon emissions, and enabling a more sustainable way of meeting global energy needs. Elucidating the structure and reaction mechanisms of electrocatalysts at electrode–electrolyte interfaces is fundamental for advancing renewable energy technologies, including fuel cells, water electrolyzers, CO2 reduction, and batteries, among others. One of the fundamental challenges in electrocatalysis is understanding how to activate and sustain electrocatalytic activity, under operating conditions, for extended time periods and with optimal activity and selectivity. Although traditional ex situ methods have provided a baseline understanding of heterogeneous (electro)catalysts, they cannot provide real-time interfacial structural and compositional changes under reaction conditions, which calls for the use of in situ/operando methods. Herein, we provide a selective review of in situ and operando characterizations, in particular, the use of operando synchrotron-based X-ray techniques and in situ atomic-scale scanning transmission electron microscopy (STEM) in liquid/gas phases to advance our understanding of electrode–electrolyte interfaces at macro- and microscopic levels, which dictate the charge transfer kinetics and overall reaction mechanisms. The use of scanning electrochemical microscopy (SECM) enables direct probing of the local activity of electrocatalysts at the nanometer scale. In addition, differential electrochemical mass spectrometry (DEMS) and the electrochemical quartz crystal balance (EQCM) enable the simultaneous identification of multiple reaction intermediates and products for mechanistic studies of electrocatalyst selectivity and durability. We anticipate that continuous advances of in situ/operando techniques and probes will continue to make significant contributions to establishing structure/composition-reactivity correlations of electrocatalysts at unprecedented atomic-scale and molecular levels under realistic, real-time reaction conditions.

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Section: Scanning and Transmission Electron Microscopy (Stem)mentioning

confidence: 93%

Section: Scanning and Transmission Electron Microscopy (Stem)mentioning

confidence: 99%

OperandoMethods in Electrocatalysis

et al. 2021

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“…E-TEM allows the introduction of water vapor because the reacting gas is in the vicinity of the sample area in this setup, and the composition can be quantified using a residual gas analyzer. However, the study of water’s influence on gas–solid reactions inside a TEM is limited due to the fear of contaminating the high-vacuum TEM columns . Recently, water vapor is able to be introduced into a windowed gas cell.…”

Section: In Situ Electron Microscopymentioning

confidence: 99%

In Situ and Emerging Transmission Electron Microscopy for Catalysis Research

et al. 2023

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Catalysts are the primary facilitator in many dynamic processes. Therefore, a thorough understanding of these processes has vast implications for a myriad of energy systems. The scanning/transmission electron microscope (S/TEM) is a powerful tool not only for atomic-scale characterization but also in situ catalytic experimentation. Techniques such as liquid and gas phase electron microscopy allow the observation of catalysts in an environment conducive to catalytic reactions. Correlated algorithms can greatly improve microscopy data processing and expand multidimensional data handling. Furthermore, new techniques including 4D-STEM, atomic electron tomography, cryogenic electron microscopy, and monochromated electron energy loss spectroscopy (EELS) push the boundaries of our comprehension of catalyst behavior. In this review, we discuss the existing and emergent techniques for observing catalysts using S/TEM. Challenges and opportunities highlighted aim to inspire and accelerate the use of electron microscopy to further investigate the complex interplay of catalytic systems.

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“…A JEOL 2200FS scanning transmission electron microscope (S/TEM), equipped with Bruker-AXS silicon-drift detector for energy dispersive x-ray spectroscopy (EDS), and an FEI Titan (60-300kV) equipped with a Gatan Quantum electron energy loss (EEL) spectrometer was used to monitor the in situ reduction of Co 0.86 Mn 0.14 O \ in H 2 . Both microscopes are equipped with CEOS GmbH (Heidelberg, Ger) aberration correctors on the probe forming lenses, MEMS-based closed-cell gas reaction (CCGR) systems (Protochips Atmosphere™), and an integrated residual gas analyzer (RGA) on the gas outlet side [3,4]. The gas-cell was purged two times with nitrogen from 100 to 0.1 Torr to remove residual O 2 , and with a final purging step of 100 to 0.001 Torr.…”

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confidence: 99%