Synthesis of porous flower-like SnO2/CdSnO3 microstructures with excellent sensing performances for volatile organic compounds

Porous flower-like SnO₂/CdSnO₃ microstructures self-assembled by uniform nanosheets were synthesized using a hydrothermal process followed by calcination, and the sensing performance was measured when a gas sensor, based on such microstructures, was exposed to various volatile organic compound (VOC) gases. The response value was found to reach as high as 100.1 when the SnO₂/CdSnO₃ sensor was used to detect 100 ppm formaldehyde gas, much larger than those of other tested VOC gases, indicating the high gas sensitivity possessed by this sensor especially in the detection of formaldehyde gas. Meanwhile, the response/recovery process was fast with the response time and recovery time of only 13 and 21 s, respectively. The excellent gas sensing performance derive from the advantages of SnO₂/CdSnO₃, such as abundant n–n heterojunctions built at the interface, high available specific surface area, abundant porosity, large pore size, and rich reactive oxygen species, as well as joint effects arising from SnO₂ and CdSnO₃, suggesting that such porous flower-like SnO₂/CdSnO₃ microstructures composed of nanosheets have a high potential for developing gas sensors.