The alkaline water splitting and oxygen evolution reaction (OER) using Co-based electrocatalysts is a promising approach to produce green H2 using electricity from renewable energies. Recent studies showed that the Co3O4 active state formation is linked to a reversible deactivation which opens up strategies to apply potentiodynamic reaction conditions rejuvenating the catalyst. But before a detailed operando understanding of the active state formation dynamics is required. In this experiment, we aim to clarify those for highly active V,Fe-containing Co3-xMxO4 electrocatalysts using operando time-resolved high-energy X-ray diffraction (HE-XRD) and link the structural findings to the catalytic deactivation under OER conditions. Thereby, we will reveal how the reversible (near-surface) restructuring as well as the potential-induced lattice strain is linked to the catalytic activity and will contribute to the understanding of decisive interfacial properties to improve electrocatalysts.