Fig. 3

a Comparison of oxygen reduction reaction activity with FeAzPc-4N-THF/oxMWCNT_50 wt% (black) and FeAzPc-4N-DMSO/oxMWCNT_20 wt% (red). b Linear sweep voltammetric curves for oxidized multiwall carbon nanotube (oxMWCNT; black dashed line), Pt/C (black solid line), FePc-DMSO/oxMWCNT_20 wt% (green), and FeAzPc-4N-DMSO/oxMWCNT_20 wt% (red). Electrolyte: O2-saturated 0.1 M KOH, scan rate: 10 mV/s, rotation speed: 1600 rpm