C2H5OH sensing characteristics of various Co3O4 nanostructures prepared by solvothermal reaction

Various morphologies of Co-containing precursors such as nanorods, nanosheets, and nanocubes were prepared by controlling the solvothermal reaction using cobalt acetate, L(+)-lysine, and oxalic acid, all of which were successfully converted into Co3O4 nanostructures without morphological variation. The gas responses of these Co3O4 nanosheets, nanorods, and nanocubes to 100 ppm C2H5OH at 300 °C were 10.5, 4.7, and 4.5 times higher than those of the Co3O4 agglomerated nanopowders, respectively. In addition, the selectivity to C2H5OH over CO and H2, as well as the response/recovery kinetics, were significantly improved. These enhanced gas-sensing characteristics were attributed to the less agglomerated nanostructures of the sensing materials.