Manipulating meso-scale solvent structure from Pd nanoparticle deposits in deep eutectic solvents
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) are 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.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC); Alexander von Humboldt Foundation
- Grant/Contract Number:
- AC52-07NA27344; AC02-06CH11357
- OSTI ID:
- 1817985
- Alternate ID(s):
- OSTI ID: 1865090
- Report Number(s):
- LLNL-JRNL-823127; 1035584; TRN: US2214549
- Journal Information:
- Journal of Chemical Physics, Vol. 155, Issue 7; ISSN 0021-9606
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigating the Variation in Solvation Interactions of Choline Chloride-Based Deep Eutectic Solvents Formed Using Different Hydrogen Bond Donors
Insights into the Solvation Characteristics of Zwitterionic Deep Eutectic Solvents Using Multiple Polarity Scales