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.