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Title: Variable Temperature and Pressure Operando MAS NMR for Catalysis Science and Related Materials

Abstract

The characterization of catalytic materials under working conditions is of paramount importance for a realistic depiction and comprehensive understanding of the system. Under such relevant environments, catalysts often exhibit properties or reactivity not observed under standard spectroscopic conditions. Fulfilling such harsh environments as high temperature and pressure is a particular challenge for solid-state NMR where samples spin several thousand times a second within a strong magnetic field. To address concerns of the disparities between spectroscopic environments and operando conditions, novel MAS NMR technology has been developed that enables the probing of catalytic systems over a wide range of pressures, temperatures, and chemical environments. In this account, new efforts to overcome the technical challenges in the development of operando MAS NMR will be briefly outlined. Emphasis will be placed on exploring the unique chemical regimes that take advantage of the new developments. With the progress achieved, it is possible to collect information on various nuclear constituents ( 1H, 13C, 23Na, 27Al, etc.) as well as assess time-resolved interactions and transformations. Operando and in situ NMR enables the direct observation of chemical components and their interactions with active sites (such as Brønsted acid sites on zeolites) to reveal the nature of themore » active center under catalytic conditions. Further, mixtures of such constituents can also be assessed to reveal the transformation of the active site when side products, such as water, are generated. These interactions are observed across a range of temperatures (-10 to 230 °C) and pressures (vacuum to 100 bar) for both vapor and condensed phase analysis. When coupled with 2D NMR, computational modeling, or both, specific binding modes are identified where the adsorbed state provides distinct signatures. In addition to vapor phase chemical environments, gaseous environments can be introduced and controlled over a wide range of pressures to support catalytic studies that require H 2, CO, CO 2, etc. Mixtures of three phases may also be employed. Such reactions can be monitored in situ to reveal the transformation of the substrates, active sites, intermediates, and products over the course of the study. Further, coupling of operando NMR with isotopic labeling schemes reveals specific mechanistic insights otherwise unavailable. Examples of these strategies will be outlined to reveal important fundamental insights on working catalyst systems possible only under operando conditions. Finally, extension of operando MAS NMR to study the solid–electrolyte interface and solvation structures associated with energy storage systems and biomedical systems will also be presented to highlight the versatility of this powerful technique.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1]; ORCiD logo [2]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Washington State Univ., Pullman, WA (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; National Institutes of Health (NIH)
OSTI Identifier:
1633403
Report Number(s):
PNNL-SA-148734
Journal ID: ISSN 0001-4842
Grant/Contract Number:  
AC05-76RL01830; R21ES029778
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Accounts of Chemical Research
Additional Journal Information:
Journal Volume: 53; Journal Issue: 3; Journal ID: ISSN 0001-4842
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Alcohols; Chemical reactions; Nuclear magnetic resonance spectroscopy; Materials; Post-translational modification

Citation Formats

Jaegers, Nicholas R., Mueller, Karl T., Wang, Yong, and Hu, Jian Zhi. Variable Temperature and Pressure Operando MAS NMR for Catalysis Science and Related Materials. United States: N. p., 2020. Web. doi:10.1021/acs.accounts.9b00557.
Jaegers, Nicholas R., Mueller, Karl T., Wang, Yong, & Hu, Jian Zhi. Variable Temperature and Pressure Operando MAS NMR for Catalysis Science and Related Materials. United States. https://doi.org/10.1021/acs.accounts.9b00557
Jaegers, Nicholas R., Mueller, Karl T., Wang, Yong, and Hu, Jian Zhi. Mon . "Variable Temperature and Pressure Operando MAS NMR for Catalysis Science and Related Materials". United States. https://doi.org/10.1021/acs.accounts.9b00557. https://www.osti.gov/servlets/purl/1633403.
@article{osti_1633403,
title = {Variable Temperature and Pressure Operando MAS NMR for Catalysis Science and Related Materials},
author = {Jaegers, Nicholas R. and Mueller, Karl T. and Wang, Yong and Hu, Jian Zhi},
abstractNote = {The characterization of catalytic materials under working conditions is of paramount importance for a realistic depiction and comprehensive understanding of the system. Under such relevant environments, catalysts often exhibit properties or reactivity not observed under standard spectroscopic conditions. Fulfilling such harsh environments as high temperature and pressure is a particular challenge for solid-state NMR where samples spin several thousand times a second within a strong magnetic field. To address concerns of the disparities between spectroscopic environments and operando conditions, novel MAS NMR technology has been developed that enables the probing of catalytic systems over a wide range of pressures, temperatures, and chemical environments. In this account, new efforts to overcome the technical challenges in the development of operando MAS NMR will be briefly outlined. Emphasis will be placed on exploring the unique chemical regimes that take advantage of the new developments. With the progress achieved, it is possible to collect information on various nuclear constituents (1H, 13C, 23Na, 27Al, etc.) as well as assess time-resolved interactions and transformations. Operando and in situ NMR enables the direct observation of chemical components and their interactions with active sites (such as Brønsted acid sites on zeolites) to reveal the nature of the active center under catalytic conditions. Further, mixtures of such constituents can also be assessed to reveal the transformation of the active site when side products, such as water, are generated. These interactions are observed across a range of temperatures (-10 to 230 °C) and pressures (vacuum to 100 bar) for both vapor and condensed phase analysis. When coupled with 2D NMR, computational modeling, or both, specific binding modes are identified where the adsorbed state provides distinct signatures. In addition to vapor phase chemical environments, gaseous environments can be introduced and controlled over a wide range of pressures to support catalytic studies that require H2, CO, CO2, etc. Mixtures of three phases may also be employed. Such reactions can be monitored in situ to reveal the transformation of the substrates, active sites, intermediates, and products over the course of the study. Further, coupling of operando NMR with isotopic labeling schemes reveals specific mechanistic insights otherwise unavailable. Examples of these strategies will be outlined to reveal important fundamental insights on working catalyst systems possible only under operando conditions. Finally, extension of operando MAS NMR to study the solid–electrolyte interface and solvation structures associated with energy storage systems and biomedical systems will also be presented to highlight the versatility of this powerful technique.},
doi = {10.1021/acs.accounts.9b00557},
url = {https://www.osti.gov/biblio/1633403}, journal = {Accounts of Chemical Research},
issn = {0001-4842},
number = 3,
volume = 53,
place = {United States},
year = {2020},
month = {1}
}

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