A Versatile Method for Ammonia Detection in a Range of Relevant Electrolytes via Direct Nuclear Magnetic Resonance Techniques

Adam C. Nielander, Joshua M. McEnaney, Jay A. Schwalbe, Jon G. Baker, Sarah J. Blair, Lei Wang, Jeffrey G. Pelton, Suzanne Zamany Andersen, Kasper Enemark-Rasmussen, Viktor Colic, Sungeun Yang, Stacey F. Bent, Matteo Cargnello, Jakob Kibsgaard, Peter Christian Kjærgaard Vesborg, Ib Chorkendorff, Thomas F. Jaramillo*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Electrocatalytic N-2 reduction to ammonia has recently attracted a great deal of interest as a possible renewable energy-driven alternative to the Haber-Bosch process. However, the detection of NH3 after attempting electrocatalytic reduction of N-2 can be hampered by low NH3 yields, ambient NH3 contamination, and the need for multistep chemical separation of NH3 from the electrolyte. Herein, we report a frequency-selective pulse nuclear magnetic resonance (NMR) method and quantify the efficacy of this method to measure the concentration of NH3 (present in the assay as NH4+) in an electrolyte after electrocatalysis. This NMR method was demonstrated to be effective in a variety of nondeuterated, nonaqueous and aqueous electrolytes, and did not require the separation of NH3 from the electrolyte. NH3 sensitivity down to 1 mu M was readily achieved with isotopic and chemical specificity. Compatible electrolytes and solvents included ethanol, tetrahydrofuran, dimethyl sulfoxide, acetonitrile, propylene carbonate, diethyl either, hexanes, and water. The efficacy of the commonly employed Berthelot method was also quantified and compared to the NMR method in a range of nonaqueous and aqueous electrolytes, including ethanol, THF, propylene carbonate, and water.
Original languageEnglish
JournalACS Catalysis
Issue number7
Pages (from-to)5797-5802
Number of pages6
Publication statusPublished - 2019


  • Nitrogen reduction
  • Ammonia detection
  • NMR
  • Electrocatalysis
  • Nonaqueous electrochemistry


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