Title: Manipulating meso-scale solvent structure from Pd nanoparticle deposits in deep eutectic solvents

Abstract

Deep Eutectic Solvents (DESs) are complex solutions that present unique challenges compared to traditional solvents. Unlike most aqueous electrolytes and ionic liquids, DESs have delicate hydrogen bond networks that are responsible for their highly sensitive compositional dependence on the melting point. Prior work has demonstrated a unique nanoscale structure both experimentally and theoretically that brings both challenges and opportunities to their adoption in traditional electrochemical processes. In this study, we use in situ sample-rotated ultra-small angle x-ray scattering to resolve the near-interface solvent structure after electrodepositing Pd nanoparticles onto a glassy carbon electrode in choline chloride:urea and choline chloride:ethylene glycol DESs. Our results indicate that a hierarchical solvent structure can be observed on the meso-scale in the choline chloride:urea and choline chloride:ethylene glycol systems. Importantly, this extended solvent structure increases between -0.3 V and -0.5 V (vs Ag/AgCl) and remains high until -0.9 V (vs Ag/AgCl). Experimentally, the nature of this structure is more pronounced in the ethylene glycol system, as evidenced by both the x-ray scattering and the electrochemical impedance spectroscopy. Molecular dynamics simulations and dipolar orientation analysis reveal that chloride delocalization near the Pd interface and long-range interactions between the choline and each hydrogen bond donor (HBD) aremore » very different and qualitatively consistent with the experimental data. These results show how the long-range solvent-deposit interactions can be tuned by changing the HBD in the DES and the applied potential.« less

Authors:

Hammons, Joshua A.  ^[1];

• Search DOE PAGES for author "Hammons, Joshua A."
• Search DOE PAGES for ORCID "0000-0003-0107-1954"

Besford, Quinn A.  ^[2];

• Search DOE PAGES for author "Besford, Quinn A."
• Search DOE PAGES for ORCID "0000-0002-1779-9176"

Ilavsky, Jan  ^[3];

• Search DOE PAGES for author "Ilavsky, Jan"
• Search DOE PAGES for ORCID "0000-0003-1982-8900"

Christofferson, Andrew J.  ^[4]

• Search DOE PAGES for author "Christofferson, Andrew J."
• Search DOE PAGES for ORCID "0000-0003-0904-6630"

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+ Show Author Affiliations

1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2. Leibniz Inst. of Polymer Research (IPF), Dresden (Germany)
3. Argonne National Lab. (ANL), Argonne, IL (United States)
4. Royal Melbourne Institute of Technology (RMIT) Univ., Melbourne, VIC (Australia)

Publication Date:

Fri Aug 20 00:00:00 EDT 2021

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC); Alexander von Humboldt Foundation

OSTI Identifier:

1817985

Alternate Identifier(s):

OSTI ID: 1865090

Report Number(s):

LLNL-JRNL-823127
Journal ID: ISSN 0021-9606; 1035584; TRN: US2214549

Grant/Contract Number:  

AC52-07NA27344; AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Chemical Physics

Additional Journal Information:

Journal Volume: 155; Journal Issue: 7; Journal ID: ISSN 0021-9606

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Ultra small-angle X-ray scattering; Molecular dynamics; Electrochemical impedance spectroscopy; Electrolytes; Solvent effect; Electrodeposition; Delocalization; Nanoparticles; Electrochemistry; Deep eutectic solvents