Fullerene-metalloporphyrin co-crystal as efficient oxygen reduction reaction electrocatalyst precursor for Zn-air batteries

Abstract

Fullerene-derived carbon materials are promising catalysts for the oxygen reduction reaction (ORR) because of the presence of intrinsic defects in the carbon cage. Moreover, the N species and metallic catalytic sites can effectively overcome the sluggish kinetics of O 2 activation. In this work, a rod-shaped tetraphenylporphyrin cobalt-C 60 cocrystal (CoTPP/C 60 ) was self-assembled and then annealed to prepare a series of N, Co-codoped carbon materials. Among the resulting CoTPP/C 60 -X materials, CoTPP/C 60 -800, which was obtained at 800 °C, demonstrated a half-wave potential of 0.824 V RHE , outstanding stability, and remarkable methanol tolerance. The superior ORR performance of CoTPP/C 60 -800 can be attributed to the presence of abundant defects, appropriate nitrogen (N) species (pyridine N and graphitic N), Co-N x sites, and Co nanoparticles. Moreover, a Zn-air battery assembled using CoTPP/C 60 -800 as the cathode exhibited a high power density of 111.7 mW•cm −2 . This study provides a new strategy for designing and synthesizing advanced ORR catalysts for Zn-air batteries.