Formaldehyde sensing by Co3O4 hollow spheres at room temperature.

Formaldehyde is a ubiquitous and high toxicity gas. It is an essential task to efficient detect owing to their toxicity and diffusion. In this work, we studied on the detection of trace amount of formaldehyde based on hollow Co3O4 nanostructure. It is found that Co3O4 hollow spheres with different structures shows distinct sensing performance towards formaldehyde at room temperature, the response value of nanosheet modified Co3O4 towards 100 ppm formaldehyde will reach 35 in 18 second, and the nanoparticle modified Co3O4 hollow sphere will reach 2.1 in 18 second, 17 in 300 second. The nanosheet modified and nanoparticle modified Co3O4 hollow sphere will reach 4 and 20 in 10 second towards 100 ppm formaldehyde at room temperature. As room temperature, the sensors do not response towards NH3, CO, etc. The sensing mechanism was proposed based on the theoretical and experimental results. The Co3O4 sensor shows that potential utility in CH2O quick sensing at room temperature.