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Title: Assessing the Impacts of Dynamic Soft-Template Innate to Switchable Ionic Liquids on Nanoparticulate Green Rust Crystalline Structures

Abstract

Switchable ionic liquids (SWILs) are promising solvents for many green chemistry applications, notably the capture and (or) subsequent catalytic hydrogenation of CO2 in addition to solvents with an inherent nm-sized “soft template” that can be used for the synthesis of nanoparticles. Despite intense studies, the structural details of how soft templates form within the solvent, and how such environments solvate catalysts or chemical precursors within SWILs remains elusive. Similarly, little is known about reaction intermediates for nanoparticle synthesis, more specifically how solvent composition and speciation influence the speciation, solvation, dispersion and nucleation of nanoparticles within. Here we report a new strategy to study the dynamic solvation environments within SWILs using nanoparticulate green rust as a model system, using combined study of X-ray absorption (XAS) spectroscopy coupled with density functional theory (DFT) calculations. In situ XAS allows direct measurements of the solvent structure, and determining the speciation of reaction intermediates, offering undisturbed measurements of air-sensitive nanocrystalline green rust within liquid environments. We present here, a study showing how solvation environments change in the SWIL and how the speciation of green rust chemical precursors change as a function of the varying solvent environment. In this in situ analysis, we newly identified structuralmore » progression from linear, square planar, then ultimately octahedral iron (Fe) complexes as reaction intermediates predicted on integrative XAS measurements and DFT calculations. This study identifies a solvated octahedral Fe hydroxide complex which we propose as the critical intermediate for nucleation and growth of nanoparticulate green rust upon removal of CO2 from the SWIL. This combined experimental and computational approach enabled by the use of a novel microfluidic device offers new insights into how dynamic solvent environment (i.e., soft template) that leads to the formation of nanoparticles such as green rust in the SWILs. In this in situ analysis, we newly identified structural progression from linear, square planar, then ultimately octahedral iron (Fe) complexes as reaction intermediates predicted on integrative XAS measurements and DFT calculations. This study identifies a solvated octahedral Fe hydroxide complex which we propose as the critical intermediate for nucleation and growth of nanoparticulate green rust upon removal of CO2 from the SWIL. This combined experimental and computational approach enabled by the use of a novel microfluidic device offers new insights into how dynamic solvent environment (i.e., soft template) that leads to the formation of nanoparticles such as green rust in the SWILs.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1];  [1];  [1];  [2]; ORCiD logo [1]
  1. BATTELLE (PACIFIC NW LAB)
  2. Brookhaven National Laboratory
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1576771
Report Number(s):
PNNL-SA-144215
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Chemical Communications
Additional Journal Information:
Journal Volume: 55; Journal Issue: 75
Country of Publication:
United States
Language:
English

Citation Formats

Zheng, Jian, Yu, Xiao-Ying, Nguyen, Manh Thuong, Lao, David B., Zhu, Yifeng, Wang, Feng, and Heldebrant, David J. Assessing the Impacts of Dynamic Soft-Template Innate to Switchable Ionic Liquids on Nanoparticulate Green Rust Crystalline Structures. United States: N. p., 2019. Web. doi:10.1039/C9CC04581C.
Zheng, Jian, Yu, Xiao-Ying, Nguyen, Manh Thuong, Lao, David B., Zhu, Yifeng, Wang, Feng, & Heldebrant, David J. Assessing the Impacts of Dynamic Soft-Template Innate to Switchable Ionic Liquids on Nanoparticulate Green Rust Crystalline Structures. United States. https://doi.org/10.1039/C9CC04581C
Zheng, Jian, Yu, Xiao-Ying, Nguyen, Manh Thuong, Lao, David B., Zhu, Yifeng, Wang, Feng, and Heldebrant, David J. Wed . "Assessing the Impacts of Dynamic Soft-Template Innate to Switchable Ionic Liquids on Nanoparticulate Green Rust Crystalline Structures". United States. https://doi.org/10.1039/C9CC04581C.
@article{osti_1576771,
title = {Assessing the Impacts of Dynamic Soft-Template Innate to Switchable Ionic Liquids on Nanoparticulate Green Rust Crystalline Structures},
author = {Zheng, Jian and Yu, Xiao-Ying and Nguyen, Manh Thuong and Lao, David B. and Zhu, Yifeng and Wang, Feng and Heldebrant, David J.},
abstractNote = {Switchable ionic liquids (SWILs) are promising solvents for many green chemistry applications, notably the capture and (or) subsequent catalytic hydrogenation of CO2 in addition to solvents with an inherent nm-sized “soft template” that can be used for the synthesis of nanoparticles. Despite intense studies, the structural details of how soft templates form within the solvent, and how such environments solvate catalysts or chemical precursors within SWILs remains elusive. Similarly, little is known about reaction intermediates for nanoparticle synthesis, more specifically how solvent composition and speciation influence the speciation, solvation, dispersion and nucleation of nanoparticles within. Here we report a new strategy to study the dynamic solvation environments within SWILs using nanoparticulate green rust as a model system, using combined study of X-ray absorption (XAS) spectroscopy coupled with density functional theory (DFT) calculations. In situ XAS allows direct measurements of the solvent structure, and determining the speciation of reaction intermediates, offering undisturbed measurements of air-sensitive nanocrystalline green rust within liquid environments. We present here, a study showing how solvation environments change in the SWIL and how the speciation of green rust chemical precursors change as a function of the varying solvent environment. In this in situ analysis, we newly identified structural progression from linear, square planar, then ultimately octahedral iron (Fe) complexes as reaction intermediates predicted on integrative XAS measurements and DFT calculations. This study identifies a solvated octahedral Fe hydroxide complex which we propose as the critical intermediate for nucleation and growth of nanoparticulate green rust upon removal of CO2 from the SWIL. This combined experimental and computational approach enabled by the use of a novel microfluidic device offers new insights into how dynamic solvent environment (i.e., soft template) that leads to the formation of nanoparticles such as green rust in the SWILs. In this in situ analysis, we newly identified structural progression from linear, square planar, then ultimately octahedral iron (Fe) complexes as reaction intermediates predicted on integrative XAS measurements and DFT calculations. This study identifies a solvated octahedral Fe hydroxide complex which we propose as the critical intermediate for nucleation and growth of nanoparticulate green rust upon removal of CO2 from the SWIL. This combined experimental and computational approach enabled by the use of a novel microfluidic device offers new insights into how dynamic solvent environment (i.e., soft template) that leads to the formation of nanoparticles such as green rust in the SWILs.},
doi = {10.1039/C9CC04581C},
url = {https://www.osti.gov/biblio/1576771}, journal = {Chemical Communications},
number = 75,
volume = 55,
place = {United States},
year = {2019},
month = {9}
}

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