Fertilizer use, fossil-fuel combustion, and industrial processes have increased nitrate concentrations in many wastewaters and watersheds to levels that threaten environmental and human health . This disruption to the nitrogen cycle primarily originates from energy intensive production of ammonia by the Haber-Bosch process, which concomitantly emits more CO2 as a byproduct than any other chemical production process . Interest in closing this portion of the nitrogen cycle motivates the nitrate electroreduction reaction (NO3RR), using water and electrons as reducing agents to produce ammonia/ammonium (NH3/NH4 + , depending on the pH), with O2 produced as a byproduct at the anode. Although reducing N 5+ in nitrate (NO 3 -) requires more electrons than reducing N 0 in the dinitrogen reduction reaction (N2RR), NO3RR circumvents the stability of the N≡N bond, substantially lowering the energetic input . Together with the ability to investigate high concentrations of reactant NO 3 -(in comparison to dissolved N2), the investigation of NO3RR targeting NH 3 /NH 4 + has seen rapid growth over relatively short timescales .