Self-assembled Co3O4 porous nanostructures and their photocatalytic activity

Co3O4 hollow microspheres were synthesized by a two-step method in ethylene glycol (EG) system. First, the cobalt oxide precursor was produced in the presence of ethylene glycol (EG) by using cobalt chloride hexahydrate (CoCl2·6H2O) and sodium acetate (NaAc) as reactants. Second, the precursor was calcined to obtain the products of crystalline cobalt oxide. The products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and scanning electron microscopy (SEM). The Brunauer–Emmett–Teller (BET) gas adsorption measurement shows that the products were porous structures with two narrow porous volume distributions. Because of the unique nanostructured hollow structure composed of nanoslices, the photocatalytic activity of the products was examined by measuring the photodegradation of methyl orange solution with ultraviolet radiation. The result shows that our products have a good photocatalytic activity.