Synthesis of Zn^sub 2^SnO^sub 4^ hollow spheres by a template route for high-performance acetone gas sensor

Hollow and porous ZnO, SnO2 and Zn2SnO4 spheres were synthesized by the hydrothermal synthesis using carbonaceous spheres as templates in combination with calcination. The structure, morphology and gas sensing characteristics of the resultant product were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and gas-sensing measurement device, and the results showed that the variety of reaction parameters such as size of the template and different precursor materials have important effects on the formation of the shell structure. Compared with the solid counterparts, the hollow structures of the obtained samples were exploited as gas sensors and exhibited improved sensing performance to a series of gases (especially with regard to acetone). Moreover, sensitivity and response/recovery time of Zn2SnO4 hollow spheres to acetone were both higher than multilayered ZnO and SnO2 core-shell, and comparing the operating temperature (240 °C) of zinc oxide and stannic oxide, zinc stannate had lower operating temperature (200 °C). The formation mechanism and acetone sensing mechanism of Zn2SnO4 hollow spheres were also discussed in detail.