Microwave-assisted rapid fabrication of Co3O4 nanorods and application to the degradation of phenol

A novel microwave-assisted hydrothermal route for preparation of Co3O4 nanorods had been developed. The process contained two steps: first, nanorods of cobalt hydroxide carbonate were obtained from a mixed solution of 50 ml of 0.6 M Co(NO3)2·6H2O and 2.4 g of urea under 500 W microwave irradiated for 3 min. Then, the cobalt hydroxide carbonate nanorods were calcined at 400 °C to fabricate pure cobaltic oxide (Co3O4) nanorods. Both nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), infrared (IR) and temperature-programmed reduction (TPR). The catalytic activity towards the degradation of phenol over Co3O4 nanorods was further studied under continuous bubbling of air through the liquid phase. The results showed that phenol was degraded into harmless products (CO2 and malonic acid). The mechanism of phenol degradation was also discussed.