Ethanol-Gas-Sensing Performances of Built-in ZrO 2 /Co 3 O 4 Hybrid Nanostructures.

The development of novel nanomaterials as highly efficient gas-sensing materials is envisaged as one of the most important routes in the field of gas-sensing research. However, developing stable, selective, and efficient materials for these purposes is a highly challenging task requiring numerous design attempts. In this work, a ZrO 2 /Co 3 O 4 composite is reported, for the first time, as a gas-sensing material for the detection of ethanol. The sensitive and selective detection of ethanol gas at 200 °C has been demonstrated for the ZrO 2 /Co 3 O 4 (0.20 wt%/0.20 wt%)-based sensor. Furthermore, the sensor showed a very low response/recovery time of 56 s and 363 s, respectively, in response to a pulse of 20 ppm of ethanol and good stability. The interesting gas-sensing property of ZrO 2 /Co 3 O 4 can be ascribed to both the porous structure, which facilitates the interaction between the target gas and the sensing site, and the p-p-junction-induced built-in electric field. These results indicate that the ZrO 2 /Co 3 O 4 composite can serve as a heterostructured nanomaterial for the detection of ethanol gas.