TY - JOUR
T1 - Effect of electrolyte cations on organic electrosynthesis
T2 - The case of adiponitrile electrochemical production
AU - Blanco, Daniela E.
AU - Atwi, Rasha
AU - Sethuraman, Sandhya
AU - Lasri, Anne
AU - Morales, Julian
AU - Rajput, Nav Nidhi
AU - Modestino, Miguel A.
N1 - Funding Information:
The authors thank Ju Hee Shin for her support on the experimental campaign. They also acknowledge the financial support provided by the National Science Foundation, the H&M Foundation through the Global Change Award and from New York University, Tandon School of Engineering, through the MAM startup fund. High performance computational resources for this research were provided by Tufts High Performance Computing center and EMSL (grid.436923.9), a DOE Office of Science User Facility sponsored by the Office of Biological and Environmental Research. This work also used the Extreme Science and Engineering Discovery Environment (XSEDE) Bridges and Comet computational resources (Charge number: TG-DMR 190087), which is supported by National Science Foundation (NSF) grant number ACI-1548562. This material is based upon work supported by the National Science Foundation under grant no. 1943972.
Publisher Copyright:
© 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
PY - 2020/12
Y1 - 2020/12
N2 - Electrolyte ions have a profound impact on the reaction environment of electrochemical systems and can be key drivers in determining the reaction rate and selectivity of electro-organic reactions. We combine experimental and computational approaches to understand the individual effect of the size and concentration of supporting alkali cations, as well as their synergies with other electrolyte ions on the electrosynthesis of adiponitrile (ADN). The size of supporting alkali cations influences the surface charge density, availability of water molecules, and stability of reaction intermediates. Larger alkali cations can help limit hydrogen evolution and the early protonation of intermediates by lowering the availability of water molecules in the near electrode region. A selectivity of 93% towards ADN was achieved at −20 mA cm−2 in electrolytes containing cesium phosphate salts, ethylenediaminetetraacetic acid, and tetraalkylammonium ions (TAA ions). Electrolytes containing only supporting phosphate salts promote the early hydrogenation of intermediate species leading to low ADN selectivities (i.e., <10%). However, the combined effect of alkali cations and selectivity-directing ions (i.e., TAA ions) is essential in the enhancement of ADN synthesis. The insights gained in this study provide guidelines for the design of aqueous electrolytes that improve selectivity and limit hydrogen evolution in organic electrosynthesis.
AB - Electrolyte ions have a profound impact on the reaction environment of electrochemical systems and can be key drivers in determining the reaction rate and selectivity of electro-organic reactions. We combine experimental and computational approaches to understand the individual effect of the size and concentration of supporting alkali cations, as well as their synergies with other electrolyte ions on the electrosynthesis of adiponitrile (ADN). The size of supporting alkali cations influences the surface charge density, availability of water molecules, and stability of reaction intermediates. Larger alkali cations can help limit hydrogen evolution and the early protonation of intermediates by lowering the availability of water molecules in the near electrode region. A selectivity of 93% towards ADN was achieved at −20 mA cm−2 in electrolytes containing cesium phosphate salts, ethylenediaminetetraacetic acid, and tetraalkylammonium ions (TAA ions). Electrolytes containing only supporting phosphate salts promote the early hydrogenation of intermediate species leading to low ADN selectivities (i.e., <10%). However, the combined effect of alkali cations and selectivity-directing ions (i.e., TAA ions) is essential in the enhancement of ADN synthesis. The insights gained in this study provide guidelines for the design of aqueous electrolytes that improve selectivity and limit hydrogen evolution in organic electrosynthesis.
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U2 - 10.1149/1945-7111/abc766
DO - 10.1149/1945-7111/abc766
M3 - Article
AN - SCOPUS:85096601171
VL - 167
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
SN - 0013-4651
IS - 15
M1 - 155526
ER -