Electrochemical CO2 reduction experiments were conducted to determine the catalytic activity of 61 NiPACN for CO2R to CO and HER (Figure ). Because NiNx sites are expected to be selective for CO2R to CO and metallic Ni is known to be nearly completely inactive for CO2R , the relative activities for CO2R and HER are an indirect measurement of the distribution of Ni-containing sites in 61 NiPACN. The CO2R experiments were performed in a 2-compartment electrochemical cell with a catalyst loading of 0.2 mg/cm 2 on the glassy carbon working electrode. The CO2R results show that increasing the 61 Ni content in the catalyst from the 0 wt% to 0.1 wt% samples (nominal Ni weights from synthesis) greatly increased the activity for CO2R without significant effect on HER rates. Thus, at this dilute Ni concentration, the dominant Ni species are dispersed Ni sites that are likely CO2R active sites. The jCO versus potential shows a characteristic plateau of ~0.3 mA/cm 2 at potentials near -1.1V vs RHE which corresponds to the onset of a mass transport limited current density (Figure ). In this case, the total number of available CO2R active sites must be significantly lower than necessary to satisfy the flat-plate limiting current of ~6 mA/cm 2 that was achieved in this cell using silver foils. This suggests that the limiting jCO current is correlated to the number of CO2R active sites. The activity of the 61 NiPACN-0.5 wt% sample supports this hypothesis because the limiting current rose to ~0.8 mA/cm 2 is observed which corresponds to an increase in dispersed Ni active site content on the electrode. The HER performance of the 0.5 wt% sample shows higher current than the 0.1 wt% and 0 wt% samples which suggests that, despite the increase in dispersed Ni active site content, there is also the possibility of Ni aggregate or other HER-active Ni species formation in this sample (Figure ). The activity of the highest loaded sample, NiPACN-1 wt%, shows different electrochemical CO2R behavior relative to the two lower loading samples. This 1 wt% sample has negligible CO2R activity, below 0.1 mA/cm 2 , and has further increased HER rates relative to the 0.5 wt% sample. Thus, at this higher loading it is likely that the sample is dominated by Ni aggregates that catalyze HER and not CO2R and very few catalytically relevant dispersed Ni sites are formed. In summary, the CO2R testing suggests that the 61 NiPACN samples with nominal Ni loadings of 0.1 wt% and 0.5 wt% contain the dispersed NiNx active sites while the 1 wt% sample contains mostly HER-active Ni aggregates.