Within this range of potentials, the majority of charge passed to nitrate results in formation of nitrite with a minority fraction designated to ammonium formation (ca. 10-20%). However, the onset of water-dissociative HER (CV at top of Figure ) increases selectivity towards ammonium at the expense of total NO3RR FE (≤ -0.6 V vs RHE), suggesting elevated H * coverage mediates hydrogenation of reduced nitrogenous species (NOx,ads). In contrast to Cu, Ni demonstrates poor NO3RR FE (10-15%) across the range of potentials