Partial current densities in the presence of 50 mM NaNO3 were determined by multiplying FE towards nitrite and ammonium by current density (Figure ). As demonstrated earlier on thin films (Figure , Figure for partial current densities), total current density (𝑗 𝑇𝑜𝑡 ) is greater for Cu/CeO2-δ-C than Cu/C-Felt. Although Cu/CeO2-δ-C shows lower FE towards NO3RR at more cathodic potentials (Figure ), the rate of NO3RR increases toward nitrite (𝑗 𝑁𝑂 2 -) and ammonium (𝑗 𝑁𝐻 4 + ) on a gravimetric basis.