Pure Zn and Cu electrocatalysts were also prepared through similar DHBT electrodeposition methods (SEM images shown in Figure ) to compare their catalytic performance with that of the Zn93Cu7 alloy. As shown in Figure , Pure Cu required a significantly lower potential than pure Zn to achieve the same total current density (Jtotal, top), while the Zn93Cu7 alloy showed an intermediate behavior, suggesting that the electrochemical NO3R is more favorable on Cu. However, pure Cu could barely produce any cyclohexanone oxime, whereas pure Zn was capable of forming cyclohexanone oxime. Notably, Zn93Cu7 attained an even higher partial current density for oxime (Joxime, bottom) at a significantly lower potential compared to pure Zn. For example, a Joxime of 32±3 mA/cm 2 was achieved at -0.94 VRHE on Zn93Cu7, compared to 10±1 mA/cm 2 on pure Zn. Although pure Cu itself was deemed inactive towards cyclohexanone oxime production, the introduction of a small percentage (7%) of Cu into Zn resulted in a significantly enhanced performance. Hence, to investigate how Zn/Cu composition influences NO3R, a series of Zn-Cu alloy catalysts were prepared by electrodeposition using precursor solutions with different Zn/Cu ratios (see Table for details). EDX analysis (Figure ) determined the composition of these samples to be Zn93Cu7, Zn85Cu15, Zn74Cu26 and Zn6Cu94. Subsequently, the Zn-Cu alloys were tested for NO3R at 100 mA/cm 2 , with the measured potentials and FEs summarized in Figure . As the Cu content increased, the NO3R could be driven at lower potentials and the FE for NH3 was significantly enhanced, consistent with previous reports that Cu is an efficient electrocatalyst for NO3 -to NH3 conversion. However, Cu-rich catalysts (i.e. Zn6Cu94 and pure Cu) resulted in low FEs for cyclohexanone oxime (<1%). The highest FE for the oxime product was achieved on Zn93Cu7 (27±3%), while pure Zn and Zn85Cu15 produced oxime with lower FEs (12±1% and 17±3%, respectively). We also note that pure Zn also produced a substantial amount of N2 (FE = 33±3%) and H2 (FE = 35±2%) compared to the other electrocatalysts.