Operando Tracking of Hydrazine Intermediate Reveals the Gerischer–Marcus Pathway for Ammonia Electrooxidation on Oxygen‐Deficient CuO

accumulation is demonstrated, linking atomic-scale defect structure to macroscopic catalytic performance. This work not only presents a paradigm for probing elusive electrocatalytic intermediates but also delivers a fundamental principle for influencing reaction pathways through defect engineering.