Preparation of Co₃O₄ hollow nanospheres and gas sensing properties

The porous Co3O4 hollow nanospheres were synthesized via hard template method by a carbon spheres templated strategy. The morphology and structure of materials were studied by SEM, XRD, FTIR, BET and XPS. The structure and gas sensing properties of Co3O4 hollow nanospheres were controlled by changing the concentration of precursor and aging time. The results show that the Co3O4 hollow nanospheres with diameter of 500nm composed by 40nm Co3O4 nanoparticles can be synthesized with 0.1mol/L precursor and aging for 48h. The surface of nanospheres is porous structure. The synthesized Co3O4 hollow nanospheres sensor have good gas response to 100×10-6-0.5×10-6 NH3 at room temperature. The gas sensitivity to 100×10-6 NH3 reaches 155.8% and the response time is 1.3s. The limit level of this gas sensor to NH3 is 0.5×10-6.