Enhanced ethanol sensing of Ni-doped SnO2 hollow spheres synthesized by a one-pot hydrothermal method

This work synthesized Ni-doped SnO2 solid solutions of single-phase rutile structure by a facile one-pot hydrothermal method, and studied their gas sensing property. Hollow microspheres were obtained, and their morphology varied with Ni content. Sensors of Ni-doped SnO2 were sensitive to presence of ethanol vapor, with a maximum response occurring at 260 °C. For the optimum composition Ni/Sn = 0.5 at.% (NS-0.5), a response of 28.9 was achieved at 260 °C for 100 ppm ethanol, which was twice that of pristine SnO2. A linear dependence of the sensor response on the ethanol concentration was observed. The ethanol response remained almost constant during a 30-day measurement. Furthermore, the NS-0.5 also exhibited excellent selectivity to ethanol against several common interfering gases. The ethanol sensing behavior and possible sensing mechanism was discussed in relation with the defect chemistry and microstructure.