Enhanced ethanol sensing properties of Zn-doped SnO2 porous hollow microspheres

Zn-doped SnO2 porous hollow microspheres with an average diameter of ∼180 nm have been prepared by a direct precipitation method using colloidal carbon sphere as template. The XRD data disclosed that the structure of the Zn-doped SnO2 microspheres was the same as pure SnO2, while the crystallite size of Zn-doped SnO2 microspheres (10.63 nm) was smaller than SnO2 (23.2 nm). The sensing measurement showed that the response (Ra/Rg) increased near linearly with the ethanol gas concentration at the operating temperature of 240 °C. Compared with SnO2 microspheres, Zn-doped SnO2 porous hollow spheres exhibited a significant improvement for the response towards ethanol at 240 °C. The response of Zn-doped SnO2 microspheres was up to 3 when the sensor was exposed to 2 ppm C2H5OH, with the response and recovery times of 7 and 4 s, respectively. Additionally, the response of Zn-doped SnO2 sensor showed slight variation after 15 weeks storage. The results indicated that Zn-doped SnO2 microspheres are of great potential for fabricating C2H5OH sensors with high performance.