A Trade‐Off Between Thermodynamics and Kinetics of O 2 Binding for Highly Active and Selective Electrocatalytic Oxygen Reduction Reaction

O₂ binding to metal ions is an essential step in the oxygen reduction reaction (ORR). Tailoring O₂ binding is anticipated to realize highly active and selective four-electron ORR. Herein, we report on fine-tuning the molecular pocket of Co porphyrins to get a trade-off between thermodynamics and kinetics of O₂ binding for ORR with high activity and selectivity. Three Co tetra(2-amidophenyl)porphyrins with an αααα structure but different steric hindrance at the po