Enhanced ethanol sensing properties of ZnO-doped porous SnO2 hollow nanospheres

Doping is an important and effective way to improve the gas-sensing properties of metal oxide semiconductors. ZnO-doped porous SnO2 hollow nanospheres were successfully synthesized by a controllable and scalable route in order to improve their sensor performance, and then characterized by X-ray diffraction (XRD), high-resolution electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS). The comparative gas-sensing properties of the pure porous SnO2 hollow nanospheres and ZnO-doped porous SnO2 hollow nanospheres were also investigated. The ZnO-doped porous SnO2 hollow nanospheres exhibited significantly enhanced ethanol sensing properties, including lower operating temperature, stronger sensitivity, faster response–recovery, and better selectivity. The response (Ra/Rg) of the prepared ZnO-doped porous SnO2 hollow nanospheres to 100 ppm ethanol at 150 °C is about 14.7, with the response and recovery times being about 10 s and 23 s, respectively. The possible gas-sensing mechanism was also discussed.