We also measured the CO2RR performance of NiPc with three different diameter CNTs in an Hcell containing CO2-saturated 0.5 M KHCO3. All samples lead only to gas products with similar FECO (Supplementary Fig. ). However, as shown in Fig. and, the NiPc/SWCNT shows higher current density and CO turnover frequency (TOFCO) in CO2RR performance than NiPc/15 and NiPc/50.