. Isotope Raman study. We used NH4Cl to replace the NH4OH as the nitrogen source. The peak at 1547 cm -1 could be originating from the C-N bond, as it shifts to 1512 cm -1 when 15 N is used. We conduct the pulsed electrolysis in varied E an , and the peak shift is same in each case. Figure . NMR spectra of electrolyte solution after using 15 NH3 to replace the 14 NH3 to produce C-N bond products. The pulsed electrolysis condition is 1s pulse at E an = -0.2 V was followed 1s pulse at E ca =-1.8 V and the loop was repeated for 30 min.