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

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).6H(2)O 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 degrees C, which is higher than that of Co3O(4) 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. (C) 2016 Elsevier B.V. All rights reserved.