Synthesis and gas sensing properties of hierarchical meso-macroporous SnO2 for detection of indoor air pollutants

Hierarchical meso-macroporous SnO2 was synthesized by a sol–gel process using carbonaceous spheres as sacrificial templates. The morphology of meso-macroporous structures can be controlled by adjusting the sintering temperature. Compared with the traditional SnO2, the hierarchical meso-macroporous SnO2 exhibited higher gas response and shorter response and recovery times in detecting indoor air pollutants including ethanol, benzene and toluene. With regard to the gas sensing property, mesopores provide plenty of active sites for surface chemical reactions, on the one hand. On the other hand, the gas diffusion in the sensing film can be improved by macropores greatly. The morphology and structures were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) respectively.