Carbon material containing M-N-C active site derived from metallocorrole complex and ZIF-8 as OER/ORR bifunctional electrocatalyst for zinc-air batteries

With superior oxygen reduction reaction (ORR) catalytic properties, M-N-C catalysts represent a viable low-cost alternative to commercial Pt/C electrocatalysts in energy storage devices. Herein, the unique M-N_x coordination structure in metallocorrole (M = Fe, Mn, Co) was innovatively utilized as the precursor for active M-N-C sites, which was loaded onto ZIF-8-derived porous carbon framework to synthesize a series of MCor@Z-C bifunctional electrocatalysts. The metallocorrole provides highly stable M-N_x active centers, while the ZIF-8-derived 3D porous carbon framework constructs effective transfer channels. The prepared MCor@Z-Cs showed good catalytic activity in both electrocatalytic ORR and OER. Of which, FeCor@Z-C exhibits the best performance, achieving a half-wave potential of 0.91 V (vs. RHE), surpassing that of the commercial Pt/C catalyst (0.85 V (vs. RHE)). Moreover, it demonstrates a low oxygen evolution reaction (OER) overpotential of merely 270 mV at a current density of 10 mA cm^-2. The zinc-air battery fabricated using FeCor@Z-C exhibits a power density of 100.8 mW cm^-2 and a specific capacity of 750 mAh g^-1.