Defect-Driven Evolution of Oxo-Coordinated Cobalt Active Sites with Rapid Structural Transformation for Efficient Water Oxidation

Reconstructing the surface nature of metal–organic frameworks (MOFs) as precatalytic structures is a promising methodology for improving electrocatalytic performance. However, regulating the structural evolution of MOFs during electrolysis remains highly uncontrollable and lacks an in-depth understanding of the role of in situ -derived active sites. Here, we suggest a simple approach to fine-tune the symmetry of Co-MOFs with an oxo-coordinated asymmetric coordination that acts as a prototypical structure motif for the oxygen evolution reaction (OER). Through a facile thermal treatment, the Co–N4 configuration of Co-MOFs transforms to the distorted Co–N3–oxo configuration of defective Co–ligand nanoclusters. By operando spectroscopic characterization, the reconstructed Co–N3–oxo structure enables a rapid structural transition toward homogeneous oxyhydroxides. Moreover, the defective natur…