Carbon spheres anchored Co₃O₄ nanoclusters as an efficient catalyst for dye degradation

Herein, we have developed an effective strategy to immobilize spinel cobalt oxide (Co₃O₄) particles of nanometer and subnanometer sizes on carbon sphere support via impregnation and deposition-precipitation methods. With carbon spheres support, very small Co₃O₄ nanoparticles of around 1-2 nm are uniformly distributed on the surface. Based on XPS analysis, the surface cobalt species are found coordinated with hydroxyl groups from carbon spheres. Among the various catalysts investigated, the Co/C-300 nanocatalyst with 1-2 nm cobalt oxide clusters exhibits the highest activity with over 99% of methyl orange degraded in less than 10 min of reaction. The higher activity of Co/C-300 nanocatalyst was attributed to small size of Co₃O₄ nanoparticles with more surface sites exposed for dye degradation reaction. The Co/C-300 nanocatalyst is reasonably stable and could be recycled for at least four runs without losing activity substantially.