Publications

Proton-Transfer Kinetics at Liquid-Liquid Interfaces

D’Antona, N.; Kelly, J.; Barnard, N.; Ardo, S.; Wang, Y.; Surendranath, Y.Markland, T.; Kempler, P.; Boettcher, S. (Under review, J. Amer. Chem Soc.), ChemRxiv, 2024.
https://doi.org/10.26434/chemrxiv-2024-sxzbn.

– Atomistic MD simulations corroborate that high partition coefficient proton-acceptors facilitate proton-transfer in the interfacial region, which is optimal for kinetic studies
– The apparent standard rate constant (k0) for a high partition coefficient proton acceptor was measured at nanopipette electrodes and found to be near the upper end of previously observed values (~3 cm/s) suggesting low energetic barriers to proton desolvation at the liquid-liquid interface

Ion-Exchange-Mediated Pre-Association Gates Interfacial PCET

Lewis, N. B.; Kelly, J.; Gardner, J. G.; Razdan, N. K.; Ardo, S.Markland, T. E.; Surendranath, Y. (Under review, J. Amer. Chem Soc.), ChemRxiv, 2024
https://doi.org/10.26434/chemrxiv-2024-8vb2n-v3

 – Interfacial proton-coupled electron transfer (I-PCET) rates to a graphite-conjugated carboxylate active site depends upon the concentration of NaClO4, a nominally innocent supporting electrolyte. Adjusted for changes in effective pH, high electrolyte concentrations inhibit the reaction when hydronium is the proton donor species but not when water is the donor.

 

– The observed effect is consistent with a mechanism where concentrated NaClO4 solutions inhibit pre-association between hydronium and the active site, with MD simulations corroborating this interpretation. These results demonstrate the relevance of a previously overlooked elementary step in I-PCET and highlight the importance of supporting electrolyte in controlling IIT reactivity.

Electrochemical Phase Interconversion Enables Homogeneous-Heterogeneous Bifunctionality in Pd-Catalyzed Vinyl Acetate Synthesis

Harraz, D. M.; Lodaya, K.; Tang, B. Y.; Surendranath, Y.  Science, 2025, accepted. https://doi.org/10.26434/chemrxiv-2024-1hvg3-v2.

– Pd catalyzed vinyl acetate synthesis is a large-scale industrial process for which the mechanism is not fully understood. Under reaction conditions, both Pd metal and Pd(II) acetate species can exist.

– Electrochemical tools elucidate the roles of Pd metal and Pd(II) during vinyl acetate synthesis.

– Interconversion between homogeneous and heterogeneous Pd species is required for catalysis, with corrosion of Pd metal to Pd(II) being kinetically relevant.

 

Synthesis of 4,5-Disubstituted o-Phenylenediamines: An Enabling Platform for Electrochemical Evaluation of Intramolecular Concerted Proton–Electron Transfer Reactions

Tang, D.; Keyes, N; Rose, J.; Gonzalez, J.; Giles, M.Surendranath, Y.; Ardo, S.;M. Minus (Under review, J. Org. Chem.) ChemRxiv, 2024. https://doi.org/10.26434/chemrxiv-2024-8772n.

– We developed three distinct and modular synthetic strategies to symmetric and asymmetric 4,5-o-phenylenediamines in as little as 2 steps from commercial starting materials

– We have shown that graphitic electrodes modified by 4,5-o-phenylenediamines host interfacial proton-coupled-electron-transfer reactivity and provide rich platforms for mechanistic studies

– Prior to our work, synthetic access to 4,5-o-phenylenediamines remained limited and designs capable of hosting intramolecular interfacial proton-coupled-electron-transfer reactivity remained elusive

 

Teaching the Concepts of Donnan Potential and Liquid-Junction Potential by Evaluating Homemade pH and Ion-Sensitive Probes Constructed Using Commercial Ion-Exchange Membranes and Reference Electrodes.

Gaieck, W.; Zhang, A.; Sabatose, A.; Ngo, M.; Schwartz, E.; White, W.; Luo, S.; Schulte, L.; Wang,
Y.; Ardo, S. (Under review, J. Chem. Educ.) ChemRxiv, 2024. https://doi.org/10.26434/chemrxiv-2024-hxgnv-v2

– We designed, implemented, and evaluated a new hands-on laboratory activity intended for students in electroanalytical chemistry courses to teach the concepts of electric potential differences formed due to ions at interfaces

– A simple two-compartment electrochemical cell was constructed from inexpensive and readily available disposable plastic cuvettes and was used to measured open-circuit potentials across commercially available ion-exchange membranes to report on the magnitude of both Donnan and liquid-junction electric potential differences

– Depending on the ion-exchange membrane used and constituents in the aqueous solutions that wetted it, the cell responded like a pH, pK, pCl, or pOH probe

 

A Nanoporous Capacitive Electrochemical Ratchet for Continuous Ion Separations

Kautz, R. J.; Herman, A.; Heffernan, E. J.; Alshochat, K.S.; Grossman, E.; Saxena, R.; Muñetón, C.; Larson, D.; Ager, J. W.; Toma, F. M.; Ardo, S.; Segev, G. A. (Under review, Nat. Mater.) arXiv, 2023. https://doi.org/10.48550/ARXIV.2309.00951.

– First demonstration of an ion pump that drives aqueous ions against a force using a capacitive ratchet mechanism that does not require redox reactions.

– Modulation of an electric potential between thin metallic layers on either face of a nanoporous alumina wafer immersed in solution resulted in persistent voltages and ionic currents indicative of directional ion pumping.

– The non-linear capacitive nature of electric double layers sustains a continuous ion flux due to its repeated charging and discharging.

 

Watt’s the Risk?: Public Understanding of Battery Usage and Storage in the United States

Segrè Cohen, A.; Bunquin, J. B.  PhysArXiv, 2024. https://doi.org/10.31234/osf.io/8ybeu — under review at Energy Research and Social Science

-An experimental survey was conducted on a representative US sample.
-Positive affect and trust in science are key predictors of battery acceptance.
-Batteries combating climate change and ones for personal use are accepted equally.

Charged communications: Understanding the dynamics of information exposure and risk perceptions in battery technology adoption

Bunquin, J. B., Segrè Cohen, A. – under review at Environmental Communication

– An experimental survey was conducted on a US sample of over 1,200 participants
-Social Amplification of Risk Framework was used to ascertain where people get their information about batteries and how these sources impact risk perception
-Battery information seems to be a special interest topic rather than one of general public interest.