Synthesis of Co ₃O ₄ nanowire arrays supported on Ni foam for removal of volatile organic compounds

Crystalline Co ₃O ₄ nanowire arrays freely supported on Ni foam are successfully synthesized using a template-free method. The effects of reaction time, concentration of reactants, and temperature on the morphology of the nanowires are studied. The results indicate that uniform Co ₃O ₄ nanowires could be synthesized at 90 °C, and a transformation of the samples' morphology from nanoparticles to nanowires to microrods is observed by controlling the concentration of the reactants. The well-ordered nanowires synthesized under the selected reaction conditions are composed of spinel Co ₃O ₄ with diameters of 500∼580 nm and lengths of 6-8 μm. These nanowires show good catalytic activity for the ozone catalytic oxidation of toluene.