Cobalt oxide synthesis via flame spray pyrolysis for enhanced oxygen evolution reaction activity

Flame Spray Pyrolysis (FSP) is a powerful technology for the selective, scalable, and cost-effective synthesis of nano-oxides with tailored composition, structure, size, and morphology. This method enables the large-scale, one-step production of homogeneous nanoparticles by exploiting the high-temperature gas-phase environment. In this work, nanostructured cobalt oxide powders synthesized via FSP are compared with commercially available Co₃O₄ nanoparticles as electrocatalysts for the oxygen evolution reaction (OER). The FSP-derived nano-oxides are produced using a solvent mixture of 2-ethylhexanoic acid (2-EHA) and ethanol in a 3:1 ratio, which promotes nucleation from the gas phase (gas-to-particle conversion). The morphology of both nanoparticle sets is examined using scanning electron microscopy (SEM), while transmission electron microscopy (TEM) is used to analyze the size and shape of the FSP-synthesized cobalt oxides. Structural and textural properties are assessed through X-ray powder diffraction (XRD) and nitrogen adsorption/desorption isotherms, respectively. Finally, the electrocatalytic performance for the oxygen evolution in alkaline environment is evaluated, comparing the activity of the FSP-synthesized CoOx nanoparticles to that of the commercial Co₃O₄. The FSP CoOx exhibits significantly enhanced electrocatalytic performance, mostly attributed to the higher specific surface area compared to the commercial powders. • Comparison of Co 3 O 4 nanoparticles synthetized via FSP and commercial ones. • Characterization via SEM, TEM XRD and BET analysis. • Oxygen evolution activity in alkaline environment of commercial and FSP powders. • Improvement in electrocatalytic performance observed with FSP CoOx. • FSP CoOx exhibit higher specific surface area than the commercial powders.