Size-controlled synthesis of porous ZnSnO₃ nanocubes for improving formaldehyde gas sensitivity

During the detection of formaldehyde, sensitivity and selectivity is still a challenging issue for most reported gas sensors. Herein, an alternative formaldehyde chemosensor that is based on porous ZnSnO₃ nanocubes was synthesized. The products are characterized by XRD, SEM, TEM (HRTEM), XPS, PL measurements and N₂ adsorption-desorption. The size of the ZnSnO₃ nanocubes is about 100 nm and the corresponding specific surface area is 70.001 m² g^-1. A gas sensor based on these porous ZnSnO₃ nanocubes shows high sensitivity and selectivity to formaldehyde. The porous ZnSnO₃ nanocube sensor could detect 50 ppm formaldehyde at about 210 °C with a response value of 21.2, which is twice as much as ethanol, and 3 times that of the other five gases. Moreover, the response of the sensor had an acceptable change after a pulse test for 90 days. The sensor can detect formaldehyde with a minimum concentration of 1 ppm, and it has a good linear relationship between 1-50 ppm formaldehyde. The gas sensor based on porous ZnSnO₃ nanocubes can be utilized as a promising candidate for a practical detector of formaldehyde due to its high gas response and excellent selectivity.