The CO2RR current density is limited in the H-cell by low CO2 solubility and mass transport in aqueous electrolyte. In order to achieve higher jMeOH, we constructed a flow cell featuring a gas diffusion electrode (Supplementary Fig. ). In the flow cell, 0.1 M KOH + 3 M KCl (instead of KHCO3) was used as the catholyte to improve jMeOH and suppress HER at high potential . The total current density in the flow cell is substantially higher (Supplementary Fig. and) than that of the H-cell at all applied potentials. The maximum jMeOH of CoPc/SWCNT reaches 66.8 mA cm -2 with a 31.3% FEMeOH at -0.9 V vs. RHE, which is 7.6 times that of jMeOH in the H-cell (Fig. ). The maximum jMeOH of CoPc/15 and CoPc/50 are 21.7 mA cm -2 (15.6% FEMeOH) and 9.3 mA cm -2 (9.3% FEMeOH) at -0.9 V vs. RHE, respectively. Additionally, CoPc/SWCNT exhibits a stable total current density with no loss for 20 min at various potentials (Supplementary Fig. ). Even at 200 mA cm -2 (-0.9 V vs. RHE), the FEMeOH is maintained at ~26% for 10 h without decay (Supplementary Fig. and).