A facile route to controlled synthesis of Co3O4nanoparticles and their environmental catalytic properties

Using ammonia and Co(CH 3 COO) 2 ·4H 2 O as starting materials, a facile and surfactant-free route to controlled synthesis of Co 3 O 4 nanoparticles was proposed. Co 3 O 4 nanoparticles with average sizes of 3.5, 6, 11, 19 and 70 nm were obtained through adjusting the ethanol amount in the solvent (the ratio of ethanol to water) or the concentration of raw materials. In this process, the presence of enough O 2 was crucial for the formation of pure Co 3 O 4 phase. The environmental catalytic properties of as-obtained Co 3 O 4 nanoparticles were investigated. The results indicated their remarkable catalysis for ozonation degradation of phenol, which denoted a promising application as catalyst in waste-water treatment.