Calculation of the yield and faradaic efficiency

Note that all error bars in this work are determined from triplicate experiments on independently prepared electrodes and are then calculated using a 90% confidence interval.

For the nitrate (NO₃⁻) and nitrite (NO₂⁻) reduction reactions, the NH₃ yield rate was calculated by Eq. (1).

For the nitrate (NO₃⁻) and nitrite (NO₂⁻) reduction reactions, the NH₃ Faradaic efficiency was calculated by Eq. (2).

In the NO₃RR, the nitrate (NO₃⁻) to nitrite (NO₂⁻) reduction Faradaic efficiency was calculated by Eq. (3).

where cNH3 is the concentration of NH_3(aq) (μg mL⁻¹), V is the volume of the electrolyte (mL), MwNH3 is the molar mass of NH₃ (17.031 g mol⁻¹), t is the duration of the chronoamperometric measurement (h), the surface area of the working electrode, A_electrode is 0.45 cm². The number of electrons transferred, n, for NO₃⁻ to NO₂⁻ is n = 2 and for NO₃⁻ to NH₃ is n = 8.

F is Faraday’s constant (96,485 C mol⁻¹), the concentration of NO₂⁻ (μg mL⁻¹), C_NO2-, where the molar mass of NO₂⁻, Mw_NO2- is (46.005 g mol⁻¹) and the charge during the chronoamperometric measurement, Q.