Constructing 3D porous SnO2 nanomaterials for enhanced formaldehyde sensing performances

3D porous SnO₂ nanomaterials enhanced gas sensitivity properties for formaldehyde has been successfully prepared by a simple template method. The morphology of the synthesized SnO₂ was observed by a scanning electron microscope (SEM) as a 3D porous structure with a pore diameter of 120 nm. We systematically studied the gas sensing performance of 3D porous SnO₂ and particulate SnO₂. The result shows that the response value of 3D porous SnO₂ to 100 ppm formaldehyde gas was 51.0 at low temperature 230 ℃, which was 6.4 times higher than that of particulate SnO₂ (8.0), and the response/the recovery time of 3D porous SnO₂ was 8 s/15 s. The minimum detection concentration of 3D porous SnO₂ was 0.5 ppm formaldehyde with the response value of 2. However, particulate SnO₂ can only be detected 10 ppm with the response value of 2. In addition, the selectivity coefficient of 3D porous SnO₂ for formaldehyde was up to 7, which is better than particulate SnO₂ (1). The reason for the enhanced sensitivity of 3D porous SnO₂ formaldehyde gas is not only related to its porous structure and smaller grain size, but also to the increase in oxygen vacancies.