In the present work, we reported the in-situ preparation of nanostructured PEO catalysts on Al substrate in a corrosive aluminate solution. The influence of treatment time on the structure, composition, and performance of the coatings was studied in detail, and the film formation mechanism was proposed with consideration of the PEO theoretical basis. The morphology study showed that the obtained samples were highly porous and evenly covered with spherical nanoparticles with diameters of 15-25 nm. The coating treated for 60 min showed a high porosity of 30.5 +/- 1.3%, in addition, an oxide film with a unique branch-like structure was formed when the duration was 120 min. The composition analysis suggested that the nanostructured coatings mainly consisted of Al2O3, and the doped Fe3O4 and CuO were enriched on the upper surface of the layer. Owing to the superior structure and high-content of active component, the specimen treated for 120 min exhibited the highest activity during the catalytic test.