Fig. 5: Alkaline NO3RR performance.
From: Sustainable conversion of alkaline nitrate to ammonia at activities greater than 2 A cm−2
a NH3 yield rate and NH3 FE of catalysts in a 1 M KOH with 56 mM NO3– electrolyte (pH = 14) for 1 h electrolysis. Catalyst mass loading: 3 mg cm−2. Resistance of catalyst: 0.156 Ω cm−2. Resistance of electrolyte: 1.45 Ω. b Kinetic isotopic effect (KIE) diagram for the ratio of NH3 yield rate in H2O to D2O solvent in a 1 M KOH with 56 mM NO3– electrolyte at −0.4 V vs. RHE. c NO3‒ removal of catalysts measured in a 1 M KOH with 56 mM NO3– electrolyte (equals 790.3 μg mL−1 NO3––N) at −0.4 V vs. RHE. After 1 h electrolysis, only 7.1 μg mL−1 of NO3––N and 0.85 μg mL−1 of NO2––N remained, both below the WHO regulations for drinking water (NO3––N < 11.3 μg mL−1 and NO2––N < 0.91 μg mL−1). d NH3 partial current densities of Pd-Cl/Cu2O in a 1 M KOH electrolyte with 1000 mM NO3– under the potential range from −0.2 to −0.6 V vs. RHE. e NH3 yield rate of Pd-Cl/Cu2O in a 1 M KOH electrolyte with different NO3– concentrations for 1 h of electrolysis. f NO3RR performance comparison of reported electrocatalysts. g Schematic of the ammonia product synthesis process from 1000 mM NO3– electrolyte to NH4Cl for 5 h electrolysis at −0.6 V vs. RHE. h The conversion efficiency of different steps for the ammonia product synthesis process. Numbers on the x-axis indicated the corresponding conversion steps in panel g. Error bars indicate the relative standard deviations of the mean (n = 3). See “Methods” for experimental details.
