Adapting Synthetic Models of Heme/Cu Sites to Energy‐Efficient Electrocatalytic Oxygen Reduction Reaction

Abstract In nature, cytochrome c oxidases catalyze the 4e − oxygen reduction reaction (ORR) at the heme/Cu site, in which Cu I is used to assist O 2 activation. Because of the thermodynamic barrier to generate Cu I , synthetic Fe‐porphyrin/Cu complexes usually show moderate electrocatalytic ORR activity. We herein report on a Co‐corrole/Co complex 1‐Co for energy‐efficient electrocatalytic ORR. By hanging a Co II ion over Co corrole, 1‐Co realizes electrocatalytic 4e − ORR with a half‐wave potential of 0.89 V versus RHE, which is outstanding among corrole‐based electrocatalysts. Notably, 1‐Co outperforms Co corrole hanged with Cu II or Zn II . We revealed that the hanging Co II ion can provide an electron to improve O 2 binding thermodynamically and dynamically, a function represented by the biological Cu I ion of the heme/Cu site. This work is significant to present a remarkable ORR electrocatalyst and to show the vital role of a second‐sphere redox‐active metal ion in promoting O 2 binding and activation.