We investigated the E1/2 of NO3-RR

We investigated the E1/2 of NO3-RR on catalysts with different Cu:Ni ratios in 1 M KOH + 10 mM KNO3 electrolyte. On Cu30Ni70, Cu50Ni50, Cu80Ni20 alloys, we found increasing NO3- RR E1/2 compared to the pure Cu catalyst. For instance, at 100 rpm, Cu50Ni50 catalyst exhibited the highest E1/2 of 0.08 V vs. RHE among all catalysts, while an E1/2 of -0.045 V vs. RHE was seen in the case of pure Cu (Fig. S11). The improvement in E1/2 further increased to ~120 mV when catalysts were tested in 100 mM KNO3 at the same rotating rate (Fig. 2a). For all NO3- concentrations, Cu50Ni50 catalysts perform better than the pure Cu as evidenced by the upshifting of E1/2 and the reduced overpotential required for the same current density (Fig. 2d and S7d).