Ethanol-sensing properties of SmFe1−xNixO3 perovskite oxides

SmFe1−xNixO3 (x ≤ 0.3) nanocrystallite powders with orthorhombic structure were prepared by a sol–gel citric method. The average crystallite sizes of SmFe1−xNixO3 powders are about 10–30 nm. The influences of Ni dopants upon electrical and ethanol-sensing properties of SmFe1−xNixO3 sensors are investigated. Compared with SmFeO3, SmFe1−xNixO3 (0 < x ≤ 0.3) present higher conductivities and lower optimal operating temperatures. The highest response to 500 ppm ethanol gas reaches 57.8 at 260 °C for SmFe0.95Ni0.05O3 sensor, with the response- and recovery-time of 30 s and 50 s, respectively. In addition, the SmFe0.95Ni0.05O3 sensor exhibits a good selectivity to ethanol. However, the high Ni dopants in SmFe1−xNixO3 (x > 0.05) seriously degrade the sensing sensitivities.