Preparation and properties of ultra-purity and nanosized ZnSnO₃ gas sensitive material

Zinc tin complex oxide (ZnSnO₃) powder was prepared by the coprecipitation method of oxalic acid and ammonia. A sensor with a high sensitivity and selectivity to ethanol was manufactured by using this powder. The composition and morphology of the powder were investigated by means of X-ray diffraction (XRD) and transmission electron microscope (TEM) respectively. Moreover, DSC-TG was also used to follow the whole reaction tracks of coprecipitation of oxalic acid and ammonia. This kind of powder was compared with other kinds of power prepared from other preparation ways such as solid-solid reaction and ammonia reaction. After heat treatment at 600°C for 30 h, a ultra-purity and nanosized ZnSnO₃ powder is obtained by using both oxalic acid and ammonia as precipitants at the same time. Moreover, the sensitivity value of the sensor made by sintered at 700°C for 2 h from ZnSnO₃ powder can reach to 13.329. An excellent selectivity to ethanol when coexisted with other kinds of gas and the outstanding stability based on continuous measurement for 30 days are obtained for the sensor.