Enhanced sensing performance of the Co3O4 hierarchical nanorods to NH3 gas

Hierarchical Co3O4 nanorods have been synthesized by a hydrothermal method which shows potential application as sensing material for gas sensor. Hierarchical Co3O4 nanorods are prepared by effective hydrothermal strategy. The morphology and structure of the hierarchical nanostructures are characterized by means of field emission scanning electron microscope, high-resolution transmission electron microscopy and X-ray diffraction. The as-prepared Co3O4 nanorods with the diameters about 200nm are composed of small nanorods with average sizes of 20nm. The gas-sensing properties of synthesized nanorods are tested to ammonia. Results reveal that hierarchical Co3O4 nanorods have excellent sensing performance. Moreover, the sensor consisting of hierarchical Co3O4 nanorods exhibits high response and fast response/recovery speed to ammonia gas, while the sensor made of normal Co3O4 nanorods do not exhibit notable response to ammonia gas. Significant enhancement of the sensing performance is attributed to the unique hierarchical nanostructure and good catalytic activity of Co3O4 nanomaterials.