High-performance FeO x @CoO x /NC electrocatalysts for the oxygen reduction reaction in alkaline media

Herein, cobalt oxide encapsulated nitrogen-doped tubular carbon (CoO x /NC) is derived via one-step carbonization of ZIF-12. Iron oxide nanoparticles are then generated over the CoO x /NC support by decomposition of the iron phenanthroline complex to obtain FeO x @CoO x /NCs. The synthesized electrocatalysts are tested for the oxygen reduction reaction (ORR). The optimized electrocatalyst FeO x @CoO x /NC2 exhibits superior activity to 20 wt% Pt/C in 0.1 M KOH with the E 1/2 = 0.89 V RHE , E onset= 1.03 V RHE and j = 6.32 mA cm −2 values. The enhanced activity is attributed to the cumulative effect of FeO x , CoO x and presence of four types of nitrogen atoms. For comparison, FeO x @MWCNTs demonstrates lower activity than the synthesized catalysts ( E 1/2 = 0.76 V RHE and E onset = 0.94 V RHE ) which proves the synergistic role of CoO x towards the ORR. The oxygen reduction reaction ability of the synthesized catalyst (FeO x @CoO x /NC2) is also investigated in the presence of 0.5 M methanol. The catalyst exhibits enhanced tolerance to methanol addition. The accelerated durability test (ADT) performed in 0.1 M KOH over 10 000 cycles shows a decay of only 17 mV.