Ultra-Rapid Synthesis of Co3O4 Nanostructures with Tunable Morphology via Nickel-Assisted Anodization

Various morphologies of cobalt oxide Co3O4 films on cobalt (Co) foils were obtained via anodization followed by a thermal treatment at 350 °C. This study introduces a rapid and cost-effective synthesis route, achieving well-defined spinel structures in only 30 min. The novelty of this work lies in exploring nickel (Ni) as a morphological modifier in the anodization electrolyte. FESEM analysis revealed that, while anodization without Ni produced nanoflake structures, the inclusion of Ni transformed the morphology into larger cubic crystals and rice grain–shaped nanoparticles. XPS confirmed the presence of oxygen vacancies during phase formation, TEM showed spinel grains smaller than 20 nm, and Raman spectroscopy exhibited characteristic peak shifts influenced by both anodization and Ni addition. These results demonstrate that Ni not only accelerates the formation of spinel Co3O4 but also plays a decisive role in tailoring morphology, highlighting the efficiency and novelty of this approach.