Highly sensitive formaldehyde chemical sensor based on in situ precipitation synthesis of ZnSnO3 microspheres

Highly sensitive formaldehyde chemical sensor was fabricated using uniform and mono-disperse ZnSnO3 microspheres, which were successfully prepared by a template-free, economical in situ precipitation method combined with subsequent calcination. The orientation and morphology of the precursor, ZnSn(OH)6 microspheres, were carefully controlled by adjusting the added amount of NaOH. This facile process may provide an approach to synthesis of functional nanomaterials with unique structures and excellent physicochemical properties. Moreover, the as-fabricated sensors based on the ZnSnO3 microspheres showed high response and short response-recovery time toward formaldehyde. To 50 ppm formaldehyde, the sensor response (S) was 17 at a working temperature of 260 °C, and the response and recovery time were 6 and 18 s, respectively. The gas response of sensors based on the ZnSnO3 microspheres was linear with the concentration of formaldehyde in the range of 5–100 ppm with a correlation coefficient of 0.997. These results showed that the as-prepared ZnSnO3 microspheres have a potential application in gas sensor.