Open circuit control experiments were conducted where no potential was applied, and the solutions were stirred for 2 hours with 6 bars of N2 pressure. NMR spectra of both pre-electrolyte and post-electrolyte samples showed no ammonia in the post-electrolyte samples, as shown in Error! Reference source not found.B. Additionally, another control experiment was performed using argon (Ar) to pressurize the reactor instead of N2. The reactor was pressurized to 6 bar with Ar, and the reaction was carried out at -15 mA/cm 2 for 4 hours. Post-electrolyte analysis using 1 H NMR showed no ammonia peaks, as shown in Figure in SI. Finally, an electrolyte sample was prepared and left open in the fume hood to ensure that ammonia was not originating from atmospheric contaminants but was instead being electrochemically synthesized. After 2 hours in the fume hood, 1 H NMR analysis showed no ammonia peaks as depicted in Figure B in SI.