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Title: Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation

Abstract

Sodium-based catalysts (such as Na 2 WO 4) were proposed to selectively catalyze OH radical formation from H 2O and O 2 at high temperatures. This reaction may proceed on molten salt state surfaces owing to the lower melting point of the used Na salts compared to the reaction temperature. This study provides direct evidence of the molten salt state of Na 2WO 4, which can form OH radicals, using in situ techniques including X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), laser induced fluorescence (LIF) spectrometry, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). As a result, Na 2O 2 species, which were hypothesized to be responsible for the formation of OH radicals, have been identified on the outer surfaces at temperatures of ≥800°C, and these species are useful for various gasphase hydrocarbon reactions, including the selective transformation of methane to ethane.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [1];  [3];  [4]; ORCiD logo [4]; ORCiD logo [2]
  1. King Abdullah Univ. of Science and Technology (KAUST), Thuwal (Saudi Arabia). KAUST Catalysis Center (KCC) and Physical Sciences and Engineering Division (PSE)
  2. Univ. of Kansas, Lawrence, KS (United States). Dept. of Chemical and Petroleum Engineering Dept. of Chemistry
  3. Protochips, Inc., Morrisville, NC (United States); North Carolina State Univ., Raleigh, NC (United States). Analytical Instrumentation Facility, Materials Science and Engineering Dept.
  4. King Abdullah Univ. of Science and Technology (KAUST), Thuwal (Saudi Arabia). Clean Combustion Research Center (CCRC) and Physical Sciences and Engineering Division (PSE)
Publication Date:
Research Org.:
Univ. of Kansas, Lawrence, KS (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1425939
Grant/Contract Number:  
SC0014561
Resource Type:
Accepted Manuscript
Journal Name:
Angewandte Chemie (International Edition)
Additional Journal Information:
Journal Name: Angewandte Chemie (International Edition); Journal Volume: 56; Journal Issue: 35; Journal ID: ISSN 1433-7851
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Takanabe, Kazuhiro, Khan, Abdulaziz M., Tang, Yu, Nguyen, Luan, Ziani, Ahmed, Jacobs, Benjamin W., Elbaz, Ayman M., Sarathy, S. Mani, and Tao, Franklin Feng. Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation. United States: N. p., 2017. Web. doi:10.1002/anie.201704758.
Takanabe, Kazuhiro, Khan, Abdulaziz M., Tang, Yu, Nguyen, Luan, Ziani, Ahmed, Jacobs, Benjamin W., Elbaz, Ayman M., Sarathy, S. Mani, & Tao, Franklin Feng. Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation. United States. doi:10.1002/anie.201704758.
Takanabe, Kazuhiro, Khan, Abdulaziz M., Tang, Yu, Nguyen, Luan, Ziani, Ahmed, Jacobs, Benjamin W., Elbaz, Ayman M., Sarathy, S. Mani, and Tao, Franklin Feng. Mon . "Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation". United States. doi:10.1002/anie.201704758. https://www.osti.gov/servlets/purl/1425939.
@article{osti_1425939,
title = {Integrated In Situ Characterization of a Molten Salt Catalyst Surface: Evidence of Sodium Peroxide and Hydroxyl Radical Formation},
author = {Takanabe, Kazuhiro and Khan, Abdulaziz M. and Tang, Yu and Nguyen, Luan and Ziani, Ahmed and Jacobs, Benjamin W. and Elbaz, Ayman M. and Sarathy, S. Mani and Tao, Franklin Feng},
abstractNote = {Sodium-based catalysts (such as Na2 WO4) were proposed to selectively catalyze OH radical formation from H2O and O2 at high temperatures. This reaction may proceed on molten salt state surfaces owing to the lower melting point of the used Na salts compared to the reaction temperature. This study provides direct evidence of the molten salt state of Na2WO4, which can form OH radicals, using in situ techniques including X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), laser induced fluorescence (LIF) spectrometry, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). As a result, Na2O2 species, which were hypothesized to be responsible for the formation of OH radicals, have been identified on the outer surfaces at temperatures of ≥800°C, and these species are useful for various gasphase hydrocarbon reactions, including the selective transformation of methane to ethane.},
doi = {10.1002/anie.201704758},
journal = {Angewandte Chemie (International Edition)},
number = 35,
volume = 56,
place = {United States},
year = {2017},
month = {7}
}

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