Synthesis of coryphantha elephantidens-like SnO2 nanospheres and their gas sensing properties

In this work, coryphantha elephantidens-like SnO₂ with porous structures were prepared successfully by a simple hydrothermal route, through adjusting the temperature of hydrotherm. Its morphology was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET). Compared to the regular nanospheres, the coryphantha elephantidens-like SnO₂ nanospheres had obviously higher gas-sensing response, owing to the special structure with large specific surface area (161.16 m² g^?1). It surprised us that the coryphantha elephantidens-like SnO₂ sensor could easily distinguish between ethanol and acetone, whose chemical property were similar. Moreover, it also exhibited wide measurement range, fast response speed (less than 10 s) and good repeatability at a low temperature (180 °C) to ethanol. The desirable specific surface area and pore volume were conducive to molecules adsorption and diffusion, which were believed to be the major cause of the improvement of gas sensing performance.