P-type Co3O4 nanomaterials-based gas sensor: Preparation and acetone sensing performance

- Typical Co3O4 nanocubes and nanospheres were prepared using one-pot hydrothermal route.
- Co3O4 nanocubes with exposure of high active Co2+ exhibits high catalytic activity.
- Gas sensor based on Co3O4 nanocubes show a high response and repaid response/recovery time (2 s/5 s) to acetone.

Uniform Co3O4 nanocubes have been prepared via an effective one-pot hydrothermal method. Sphere-shape Co3O4 nanomaterials can be synthesized by varying the concentration of Co(NO3)2·6H2O and NaOH without the utilization of surfactants. Co3O4 nanocubes and Co3O4 nanospheres show regular geometry structure with diameters of 250 nm and 300 nm, respectively. Gas sensors based on different Co3O4 nanostructured are fabricated and used for investigating acetone sensing performances. The response of Co3O4 nanocubes based sensor to 500 ppm acetone is 4.88 at 240 °C, which is higher than that of Co3O4 nanospheres. In addition, sensors based on Co3O4 nanocubes not only exhibit a high response but also have a rapid response time (2 s) and recovery process (5 s) to acetone. The enhanced sensing performances to acetone can be attributed to the effective catalytic activity of Co2+ at special low-index crystal facets. This finding demonstrates the shape-related synthesis of nanomaterials can be an effective way of designing high performance gas sensor, and also provides a new insight into gas-sensing mechanism.

Typical Co3O4 nanocube with exposure of high active Co2+ were prepared using one-pot hydrothermal route and exhibited higher acetone response than that of Co3O4 nanosphere.139